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Imperishable Night/Gameplay

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Title screen of the game

Gameplay

Controls

The game may be played using either a keyboard or a gamepad.

Keyboard controls are as follows:

  • The Arrow Keys move the character around
  • Z causes a short barrage of shots to be fired; it may be held down for rapidfire
  • X releases a bomb, also known as a Spell Card (presuming that any are left)
  • Shift slows the character's movement, and changes the nature of the character's shot and bomb; it generally makes your attacks more focused
  • Esc pauses the game and brings you to the in-game menu
  • Ctrl fast-forwards through any dialogue
  • Home or P produces a .bmp screenshot in the /snapshot directory.
  • Q returns you to the title screen when the game is paused
  • R returns you to the beginning of stage 1 when the game is paused

Basic Gameplay

Imperishable Night plays like a fairly typical vertically-scrolling danmaku shooting game, in which the player's character is always facing towards the top of the screen, shooting at anything that moves, avoiding and weaving between enemy bullets, and confronting difficult bosses at the end of a stage.

There are 4 levels of difficulty: Easy, Normal, Hard, and Lunatic. Each difficulty level features differences in the number of bullets fired by each enemy, rate of fire, variations in the bullets' pattern of movement, and the number and type of enemy Spell Cards used.

In this system, the game starts at 11:00 pm, and one hour is added after each stage. If enough time orbs are collected in the stage, half an hour is added for that stage instead. Half an hour is also added every time a continue is used. If the time reaches 5:00 am before the end of the last stage, the player receives a Game Over.

Shot

A character's "shot" is the player's primary method of attacking enemies. While the shot's attack area and behavior varies depending on the character type the player has chosen, the shot can be powered up by filling up the Power Level by collecting power items. The shot gradually becomes more powerful when the player reaches the Power Levels of 8, 24, 48, 80, and 128 (MAX), respectively. When the player reaches MAX power, all bullets on the screen cancel out and become star items which are automatically collected. While the player has maximum shot power, the player may auto-collect all items on screen by moving their character close to the top of the screen (see point of collection). New to Imperishable Night, you may also auto-collect without maximum shot power by focusing above the point of collection. Note that the Human side in a team are for unfocus shot whereas Youkai side are for focused shot (see Characters section).

Shot Types

Illusionary Barrier Team

Reimu

Shot: Mind Amulet (「マインドアミュレット」)
Spell Card: Spirit Sign "Dream Orb" (霊符「夢想妙珠」)
Last Spell: Divine Spirit "Dream Seal -Blink-" (神霊「夢想封印 瞬」)

Yukari

Shot: 「妖回針」 ("Apparotation Needle") [1]
Spell Card: Border Sign "Quadruple Barrier" (境符「四重結界」)
Last Spell: Boundary "Quadruple Barrier of the Imperishable Night" (境界「永夜四重結界」)


Aria of Forbidden Magic Team

Marisa

Shot: Stardust Missile (「スターダストミサイル」)
Spell Card: Love Sign "Master Spark" (恋符「マスタースパーク」)
Last Spell: Magicannon "Final Spark" (魔砲「ファイナルスパーク」)

Alice

Shot: Spectrum Mystery (「スペクトルミステリー」)
Spell Card: Magic Sign "Artful Sacrifice" (魔符「アーティフルサクリファイス」)
Last Spell: Magipulation "Return Inanimateness" (魔操「リターンイナニメトネス」)

Visionary Scarlet Devil Team

Sakuya

Shot: Mysterious Jack (「ミステリアスジャック」)
Spell Card: Illusion Sign "Killing Doll" (幻符「殺人ドール」)
Last Spell: Buriallusion "Phantomic Killer in Night Mist" (幻葬「夜霧の幻影殺人鬼」)

Remilia

Shot: Night Dance (「ナイトダンス」)
Spell Card: Scarlet Sign "Red the Nightless Castle" (紅符「不夜城レッド」)
Last Spell: Scarlet Magic "Scarlet Devil" (紅魔「スカーレットデビル」)

Netherworld Dwellers' Team

Youmu

Shot: Bizarreness of Six Realms (「六道怪奇」)
Spell Card: Human Sign "Slash of the Present World" (人符「現世斬」)
Last Spell: Human Oni "Slash of the Eternal Future" (人鬼「未来永劫斬」)

Yuyuko

Shot: Invitation from the Nether Side (「対岸の誘い」)
Spell Card: Death Sign "Ghastly Dream" (死符「ギャストリドリーム」)
Last Spell: Deadly Butterfly "Eternal Sleep in Dreamland" (死蝶「華胥の永眠」)

Bomb

A character's "bomb" is the player's limited-use method of getting out of difficult situations. A bomb's attack area, duration, and power varies depending on the character type the player has chosen and if the player is in human form or youkai form, but it typically deals heavy damage to every enemy it touches, in addition to canceling out any bullets in the bomb's way, as well as automatically collecting every item on screen. The player's character becomes invincible during and for a short time after the bomb's effect wears off. At the beginning of the game and any time your character respawns, you will start off with 3 bombs. Bomb items will increase your current stock by one. You can carry up to a maximum of 8 bombs at a time. If you receive a bomb when you already have the maximum, that bomb will be lost.

If you got hit, you can use Last Spell to avoid losing a life. You must bomb within 0.1-0.9 seconds of getting hit (depends on which team you chose, the number of bombs you have left, and if you're facing a boss's spellcard or not). This short time interval is called "the border between life and death". A last spell uses two normal bombs (or one if you only have one), but is more powerful and lasts longer. Unfortunately, you still lose a lot of time orbs (as if you had gotten hit) if you use last spell.

Also, although it's not as widely known, the normal counter-bomb (or "deathbomb") from previous entries is present in this title as well. After your character is hit by an enemy shot, there is an extremely short window where bombing will activate a normal spellcard, not a Last Spell, and the game will continue as if you had not been hit at all.

Lives

With default settings, you will start off with 3 lives. You can lose a life by getting "hit" by an enemy attack.

The hit box for your character is quite small in comparison to your on-screen sprite, approximately only 5 pixels by 5 pixels in size. If you hold Shift, a colored dot will appear, showing the hitbox precisely. If the hit box of your character's sprite comes into contact with the hit box of an enemy bullet, laser, or the enemy itself, then you have been hit.

The player is awarded extra lives upon reaching certain point item totals (not by raw points, unlike the two following games) or by collecting 1up items. For the regular game, extra lives are awarded at 100, 250, 500, 800 and 1100 point items, and a 1up item is dropped after defeating the midboss in stages 3 and 5. For the Extra Stage, extra lives are awarded at 200 and 666 point items, and a 1up item is dropped after defeating the midboss and after defeating the last enemy in the regular stage. You can carry up to a maximum of 8 extra lives at a time. If you receive an extra life when you already have the maximum, you will receive a bomb instead.

When you lose a life, you also lose 16 Power points (13 are scattered for you to collect). Also, all the bullets on the screen are cleared, and you become invulnerable for a short period of time.

Upon losing all your lives, you are given the option to continue right where you left off. You may continue until 4:30am (because continuing would advance you to 5:00am); however, you may not continue at all in FinalB or the Extra stage. In addition, if you do continue, your current score will be reset back to 11 x the number of times you have continued, your current score will not be saved, you will not be able to save a replay of your game, and you may only proceed to FinalA (not FinalB) after completing stage 5.

Youkai Gauge

In Imperishable Night, anything not classed as a human is classed as a youkai. All youkai have a familiar, sometimes called slave, which gives them additional firepower (bosses often have many familiars who cover the screen with bullets).

The youkai gauge ranges from -100% (human) to 100% (youkai). If you kill enemies as a human (unfocused), your youkai gauge will move towards -100%. If you kill enemies as a youkai (focused), your youkai gauge will move towards 100%. As you become more human, your shots become blue. As you become more youkai, your shots typically become more red.

Destroying enemy familiars will push your gauge toward 0%. Familiars may only be hit while the player is in human form. The automatic destruction of a familiars due to its master being defeated does not cause this effect (it instead causes the familiars to become some time orbs).

Collecting purple time orbs will push your gauge toward 100% of whatever form you are in. Two possible sources of these are spell card bonuses and enemy familiars (when they are detonated due to their master being defeated).

When you reach 80% you can collect time orbs by hitting enemies (as a human) or by grazing against bosses and killing enemies (as a youkai). Since it's important to collect as many time orbs as possible (to slow time and get high scores), you must try to keep your gauge either below -80% or above 80%. If your gauge can't ever reach 80%, you can collect time orbs when you reach 30%. If your gauge can't ever reach 30%, you cannot collect time orbs while at that end of the gauge.

If you bomb, you will push the gauge to 100%(focused) or -100%(unfocused). Using a Last Spell will push your gauge the opposite direction. If you die, you will push the gauge to 0%. If you do nothing, your gauge will slowly move to 0% (this effect may be avoided by constantly switching between human and youkai forms).

Youkai Gauge Summary Table
Team/character Youkai Gauge Hitting enemies for orbs Grazing for orbs
Netherworld Team -50% to 100% -50% to -30% 80% to 100%
Other teams -100% to 100% -100% to -80% 80% to 100%
All Youkai -20% to 100% None 80% to 100%
Youmu -50% to 50% -50% to -30% 30% to 50%
Other humans -100% to 20% -100% to -80% None

Difficulty Level

Like most of the other Windows games, Imperishable Night has descriptions and alternate names for each of the difficulty levels.

Easy - New moon - For people who don't play Touhou very much.
Normal - Waxing Crescent moon - For people who play Touhou often.
Hard - First Quarter moon - For those who often play STGs.
Lunatic - Waxing Gibbous moon - Not suited for anyone.
Extra - Full Moon - The moon drives people mad.

Stages

There are 6 stages in the main game:

  1. Stage 1: Destination of the Fireflies (「蛍火の行方」)
  2. Stage 2: The Path Where Humans Vanish (「人間の消える道」)
  3. Stage 3: The History-Eater's Nostalgia (「歴史喰いの懐郷」)
  4. Stage 4:
    • Uncanny: Legendary Paradise (「伝説の夢の国」)
    • Powerful: Underneath the Mana-Saturated Soil (「魔力を含む土の下」)
  5. Stage 5: A Pure Cage of the Filthy World (「穢き世の美しき檻」)
  6. Final Stage
    • A: Princess-Concealing Orb in the Night Sky (「姫を隠す夜空の珠」)
    • B: Five Impossible Requests (「五つの難題」)

There are two branches in the stage listing. In stage 4, you go to Uncanny if you're Marisa/Alice or Sakuya/Remilia and you go to Powerful if you're Reimu/Yukari or Youmu/Yuyuko. In practice mode, you unlock the ability to choose the other stage 4 when the team (or character) has completed FinalB.

If it's your first time with a team at the Final Stage, you automatically go to A. If you've completed the game with FinalA (on any difficulty, not necessarily the one you are currently playing), you go to FinalB. If you've beaten it with A and B, you get to choose (FinalB is harder than FinalA). However, you cannot choose FinalB if you continued during the game. Once all teams have completed both FinalA and FinalB, solo characters are unlocked, and immediately have the option to choose either final.

Once the game has been completed (both FinalA and FinalB), an Extra Stage is unlocked. The Extra Stage features significantly stronger and faster enemies, an extremely difficult midboss and boss battle, and no option to continue if all lives are lost.

Boss Battles

The main challenge and the main attraction. Each boss has multiple lives, which are represented by multiple health bars shown at the upper left of the screen. Bosses usually alternate between attacking normally and attacking with Spell Cards, switching once with each health bar. The attack are slightly different based if the player is focus or unfocus. Colored sections on the health bar indicate the start of a Spell Card attack when the boss' health is depleted that far.

Normal attacks are incrementally stronger versions of the boss character's basic attack. Spell Card attacks bedazzle the player with combinations of complex patterns that often involve the use of projectiles and obstacles crafted especially for use with that Spell Card. If the player manages to defeat a Spell Card attack without getting hit or using any bombs, a substantial score bonus is rewarded for the feat.

Each attack is accompanied by a timer. When time runs out, the boss will switch to their next attack pattern even if their health bar isn't empty. Waiting for a boss character's attack pattern to self-destruct may be enough to beat them, but mere survival won't earn the player any score bonuses. (Note: There are some spell cards in which the boss is invulnerable. For those cards, you WILL get a score bonus if you survive the countdown to zero.)

When fighting a boss, a position marker shows up on the bottom margin of the screen, indicating where the boss is on the horizontal axis. Since your target can be completely obscured by bullets or darkness at times, use this marker to help you aim your shots. The marker will dim when the boss is being hit, and will flash red when her health bar gets sufficiently depleted.

If you meet the time orb requirement for the stage and are not playing at Easy difficulty, the boss will finish off with at least one last spell (the equivalent of the boss using a counter-bomb before she dies). These spells are significantly harder than the main spell cards but are a way to earn bonus points. You cannot use bombs or lose life in a last spell (it simply fails if you get hit). During a last spell, your number of extra lives and bombs is crossed out with a red and white "x" and the word nullify.

Screen Layout

Screen Layout
  1. Your character
  2. Player Score
    • High Score: your highest score for the current character, type, and difficulty
    • Score: your current score
  3. The number of remaining lives and bombs / The approximate location of the point of collection
  4. Player Status
    • Power: your shot power level, maxing out at 128
    • Graze: the number of enemy shots that have grazed your hitbox during the game
    • Point: the number of point items you have collected during the game and the amount needed for an extra life
    • Time: the number of time orbs you have collected during this stage and the amount needed to slow time by 0:30 for this stage
  5. Enemy Status
    • Left bar(s): the number of health bars the enemy has left. White bars indicate the boss will use regular attacks, red bars indicate the boss will use a spell card.
    • Right number: the amount of time left before the enemy's attack spell fails (self-destructs)
  6. Youkai Gauge
    • The percent human or youkai
    • Blue means human (人)
    • Red means youkai (妖)
  7. Spell Card Status
    • Title: the name of the Spell Card being used
    • Bonus: the constantly-updating value of the Spell Card Bonus
    • History: the number of times you have "collected" the Spell Card currently being used, and the number of times you have faced it.

Unlockable Features

  • Level Practice: This feature allows a character/team to practice a level that she/they have already beaten. You begin with 9 lives and 3 bombs. If you lose all your lives, you can't continue.
  • Spell Practice: This feature allows a character/team to practice a spell they have already seen. By beating enough spells in Spell Practice, you can unlock Last Word Spell cards. Spell Practice is unlocked by beating the game with the normal ending (i.e. before the game time reaches 5:00 am). (To select a team in spell practice, press left or right and the team shown in the background will change.) Note: In Spell Practice, all cards are played as Last Spells (i.e. sudden death, no bombs).
  • Play as Individual Character: This feature allows you to play as an individual rather than as a team. To unlock this, all teams must have beaten both FinalA and FinalB.
  • Last Word Spell Cards: These are spell cards that are typically earned by accomplishing certain feats such as beating the game using certain characters/difficulties or seeing/mastering a sufficient number of spell cards. See Last Word Spell Cards for details.
  • Starting Lives: This feature lets you increase the starting lives to 6 or 7 in the options screen. These are unlocked by getting a certain number of Game Overs (not Bad Endings). Unlike Embodiment of Scarlet Devil, increasing your starting lives does not hinder your ability to gain additional lives throughout the game (because additional lives are awarded for quantities of point items, not score).

Full Unlock Code

To unlock all unlockable content at once, navigate to the Score Ranking menu and hold either Shift or Ctrl, then press Right five times, Left one time, D two times and Q three times. If done correctly, the 1up sound effect will play and the practice mode stages, spell cards (including Last Word spell cards) as well as the Extra Stage will be unlocked for all shottypes, including the solo characters.

Characters

Illusionary Barrier Team

Team Characteristics:
Small hitbox.
Long reaction-time given for using Last Spells.
Can use a Last Spell with only one bomb remaining.

Reimu Human Side

Special Skill: Doesn't get hurt when colliding with an enemy familiar.
Normal Speed: ★★★★
Focused Speed: ★

Yukari Youkai Side

Familiar: Yakumo Summoning Shiki (「召喚八雲式」)
Normal Speed: ★★★★
Focused Speed: ★


Aria of Forbidden Magic Team

Team Characteristics:
Large hitbox for items.
Large item auto-collection area.

Marisa Human Side

Special Skill: Item auto-collection is enabled even when shot power is not maximum.
Normal Speed: ★★★★★★
Focused Speed: ★★

Alice Youkai Side

Familiar: 「上海人形」 ("Shanghai Doll")
Normal Speed: ★★★★
Focused Speed: ★★


Visionary Scarlet Devil Team

Team Characteristics:
Large hitbox for grazing.
A bomb item is released when hit, if the previous life had unused bombs.

Sakuya Human Side

Special Skill: The item falling speed becomes slower.
Normal Speed: ★★★★
Focused Speed: ★★★

Remilia Youkai Side

Familiar: Servant Flier (「サーヴァントフライヤー」)
Normal Speed: ★★★★★★
Focused Speed: ★★★


Netherworld Dwellers' Team

Team Characteristics:
The human side of the ratio meter is half-size.
An extra bomb is rewarded for each completed stage (if the current number of bombs is less than 3).

Youmu Half-Human Side

Special Skill: Youmu's phantom half fires in the opposite direction of the player's last button press (i.e. if the player moves left, it will fire to Youmu's right).
Familiar: 「半幽霊」 ("Phantom Half") ( If playing Youmu alone, focusing will lock the Phantom's shot )
Normal Speed: ★★★★★★
Focused Speed: ★

Yuyuko Youkai Side

Familiar: Deadly Butterfly (「死蝶霊」)
Normal Speed: ★★★★
Focused Speed: ★


Character Shot Overview

Illusionary Barrier Team:

  • Reimu: spread + homing, medium strength
  • Yukari: forward, strong
  • Familiar: homing, weak


Aria of Forbidden Magic Team:

  • Marisa: forward, strong
  • Alice: narrow forward, strong
  • Malice Cannon*: very strong


Visionary Scarlet Devil Team:

  • Sakuya: spread, weak
  • Remilia: narrow forward, medium strength
  • Familiar: stationary forward, medium strength
  • Remilia + Familiar: very strong


Netherworld Dwellers' Team:

  • Youmu: forward, strong
  • Familiar: multi-directional, medium strength
  • Youmu + Familiar: very strong
  • Yuyuko: spread, medium strength**


Note1: the "Malice Cannon" (short for "Marisa + Alice Cannon") - tapping shift repeatedly so that Marisa shoots while Alice's laser also stays on the screen - is the strongest shot type (if there are few enemy familiars, slightly stronger than Youmu), and can deal significantly more damage than every other character if Alice's laser hits multiple enemy familiars. For example, it can deal damage in Mokou's survival and end it before the timer counts down to 00s.


Note2: For Yuyuko, medium strength = 2 streams of butterflies hitting. If only 1 stream hits, it's weak (weaker than Reimu, but still stronger than Sakuya!!). It is possible to get 3 streams to hit at about halfway up the screen, and that'd make her about as strong as Marisa or Alice. Yuyuko at point blank is as strong as Youmu.

Scoring

Enemies

Any damage you deal to any enemy, whether caused by your shots or your bombs, will cause your score to increase very slightly. Actually destroying enemies will award you slightly more points, but the points earned from this are around the range of hundreds to thousands of points per enemy. This is not a significant amount at all. However, enemies shoot bullets for you to "graze" and release items for you to collect, and those are very important for scoring as covered below.

Grazing

"Grazing a bullet" means to have a bullet or laser come dangerously close to your hitbox. Depending on your youkai gauge, the points for grazing and the number added to the graze counter per bullet differ:

Youkai gauge Score value Counter value
Youmu Solo Ghost Team Other Characters
-50% to -30% -50% to -30% -100% to -80% 2,000 3
-30% to -20% -30% to -20% -80% to -20% 2,000 2
-20% to 20% -20% to 20% -20% to 20% 2,000 1
20% to 30% 20% to 80% 20% to 80% 4,000 1
30% to 50% 80% to 100% 80% to 100% 4,000 1

You can only graze a bullet once, so you won't gain any additional points or graze by following a bullet. Lasers can be continually grazed throughout their duration, but once again, moving around will not gain you any additional points or graze.

Point Items

As the name implies, point items are the major source of points in the game. The higher up on the screen you collect them, the more points they are worth, up to a defined maximum. You can easily tell when you are collecting point items for their maximum value, since they show the value in yellow text. The auto-item-collect line is the same height as the height where point items reach their maximum value, so take advantage of this fact whenever you can for massive points.

The maximum value of a regular point item is listed under the youkai gauge. Below the point of collection point items are worth between less than 20% (at the very bottom of the screen) and 50% (just below the POC) of their maximum value. The value of all point items is doubled when the player is below -80% (or -30%, with Youmu).

Mini-point items (little blue circles) are worth 1/10 of a regular point item.

The point value increase by 10 for every 2 time orbs that are collected.

The starting values are:

Easy 60,000
Normal 100,000
Hard 200,000
Lunatic 300,000
Extra 300,000

Power Items

Power items increase the power of your shot. While your shot is not fully powered up, power items are worth only 10 points. Once fully powered up, all power items currently on the screen become (Mini-)Point items. While the character is at max power, power items no longer appear, and Point items appear instead.

Large power items are worth 8 normal power items. There is also a full power item (it's yellow), which appears if you continue. It brings you to full power and is worth 300 points. It is worth 1000 points if you are already at full power.

Time Orbs

Exclusive to Imperishable Night, they are believed to slow the passing of the night. Time orbs are essential to scoring in the game. The value of a time orb depends on the number of total point items you have collected. They are worth [# of large point items / 2] X 10, and the minimum value of a time orb is 100 points.

Time orbs appear in one of six ways:

  • Collecting a spell card bonus
  • Damaging enemies in human form while the gauge is under -80%
  • Grazing while the gauge is over +80% (only when a boss/mid-boss is present) (can be done either in human or youkai form, but in human form the time orbs will move the gauge away from +80%)
  • Destroying enemies while in -80% human mode or +80% youkai mode
  • Destroying familiars, either by depleting their own health or by destroying their master
  • Cancelling bullets by destroying familiars

The effects of collecting them are:

  • If a certain number is collected in a stage (see below for requirements), the game clock only advances 30 minutes, as opposed to an hour. In addition, in stage 1-5 on Normal or higher difficulty, you get to try the corresponding stage boss's last spell.
  • For every two orbs collected, the point counter increases by 10 points.
  • Each time orb that is collected in human mode bumps the youkai gauge toward the human side. The reverse happens when a time orb is collected in youkai mode.
  • Collecting a time orb during a spell card will increase the spell card bonus by 8000 points. However, during spells where the bonus decreases over time, this will not allow the bonus to increase beyond its starting value.

Familiars and time orbs are related. In boss battles, the numbers of familiars on screen are shown on top left of the screen.

  • First number = a = number of familiars on screen
  • Bracketed number = b = total number of familiars that weren't destroyed

For example, in a boss fight, if +11(78) is shown in the top left screen, that means a = 11, b = 78.

The formula for the number of time orbs created due to familiars on defeating a boss's life bar segment is different depending on whether the player is using a team or a solo character:

For teams

0 < a <= 8 familiars: 10 * a + 2 * a * a + 2 * b
a > 8 familiars: 26 * a + 2 * b

For human solo

0 < a <= 4 familiars: 16 * a + 6 * a * a + 2 * b
a > 4 familiars: 40 * a + 2 * b

For youkai solo

0 < a <= 10 familiars: 6 * a + 2 * a * a + 2 * b
a > 10 familiars: 26 * a + 2 * b

In stage portion the above formulae still apply except that a = b. The number of time orbs gained is summarised in the table below:

Type 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Team 0  14  32  54  80  110  144  182  224  252  280  308  336  364  392  420
Solo Human 0  24  60  108  168  210  252  294  336  378  420  462 504  546  588  630
Solo Youkai 0  10  24  42  64  90  120  154  192  234  280  308  336  364  392  420

When there are no familiars on screen there will be no time items (a = 0).

The above familiar-timeorbs formulae do not calculate bullet cancel from destroying familiars.

Using a standard bomb will not reduce the time orb level. Dying or using a Last Spell will give a penalty to the counter, however.

Star Items

These items appear any time an enemy bullet is canceled out. This can happen when you defeat an attack pattern of a boss (by depleting their current health bar), at the moment you gain maximum shot power, when you destroy a certain enemy, or when you erase enemy bullets with a bomb. The point values of star items is based on the number of grazes you have. The formula is as follows: int(graze/40)*10+300. For example: if you have 10 grazes, each star item will be worth 300 points (0+300), and if you have 4039, each star item is worth 1300 points (1000+300).

Enemy Bullet Bonus

When you finish off one of the boss's lives (caused by completely depleting the visible healthbar) or defeat a Spell Card of a boss, all enemy bullets on screen are tallied up to calculate the Enemy Bullet Bonus. The more enemy bullets there are on screen, the higher this bonus becomes. This bonus is independent of any star items collected from finishing off a boss's attack pattern. Finding the correct time in a boss's attack to finish them off can mean the difference between an Enemy Bullet bonus of 100,000 and one of 4,000,000 or more.

The formula that the game uses to calculate the bullet bonus is as such: The first bullet that is on the screen is worth 2000 points. For each bullet after this, its value increases by 20, up to the max of 8000 points per bullet. For example, the first bullet is worth 2000, second is 2020, third: 2040, fourth: 2060, and so on till the 301st and beyond bullets are worth 8000 points each. It follows that the maximum bonus is 11,385,000, at the bullet cap of 1536 bullets.

Spell Card Bonus

Occasionally, a boss will attack using a Spell Card. You will know this is happening when the background changes and the Spell Card's name appears in the upper right corner of the screen. If the boss's health bar is depleted within the time limit and without getting hit or using a bomb, the Spell Card bonus will be added to your score. The starting value of the bonus depends on the Spell Card used:

Stage 1 spells 10,000,000
Stage 2 spells 15,000,000
Stage 3 spells 20,000,000
Stage 4A/4B, most spells 22,000,000
Stage 4A/4B, final normal spell and Last Spell 25,000,000
Stage 5 normal spells 26,000,000
Stage 5 Last Spell 30,000,000
Stage 6A/6B normal spells 30,000,000
Stage 6A/6B Last Spells 33,000,000*
Extra stage midboss spells 40,000,000
Extra stage boss spells, except survival spells 45,000,000
Spell #203: "Possessed by Phoenix" 10,000,000*
Spell #205: "Imperishable Shooting" 10,000,000*
Last Words, except survival spells 99,999,990
Spell #215: "Innate Dream" 60,000,000*
Spell #216: "Blazing Star" 60,000,000*
Spell #222: "Profound Danmaku Barrier -Dreams, Illusions, Bubbles, and Shadows-" 10,000,000*

As the time remaining decreases, the bonus decreases in value as well. For each time orb collected during the Spell Card (either from grazing as a youkai, or shooting as a human), 8000 points are added to the Spell Card bonus. However, the bonus cannot increase past its initial value, except for survival Spell Cards.

The rate of decrease is equal to (initial value) / (7 * time limit in seconds * 10) per frame, rounded to the nearest 10, or (initial value) / (time limit in seconds) * 6/7 per second rounded to the nearest 600. The decrease begins immediately and is constant for the entire duration of the spell card.

Certain spell cards are considered survival spells. For these spell cards, the boss is usually invulnerable, but you can receive the spell card bonus by surviving until time runs out without dying or using a bomb. The bonus also does not decrease over time, and can increase past its initial value by collecting time orbs, up to a maximum of 99,999,990. The survival spells are marked with an asterisk in the above table.

Clear Bonus

At the end of each stage, the player is awarded a point bonus based on their performance throughout the stage. The bonus is calculated as follows:

Stage       10,000,000 (Stage 1)
            15,000,000 (Stage 2)
            20,000,000 (Stage 3)
            25,000,000 (Stage 4, Uncanny or Powerful)
            30,000,000 (Stage 5)
            35,000,000 (FinalA)
            40,000,000 (FinalB)
            66,600,000 (Extra)
Point     x     50,000 (point items collected in the stage)
Graze     x        500 (graze count for that stage)
Time Orbs x      1,000 (time orbs collected in the stage)

In addition, if the stage happened to be the last stage, the following is added:

Player      x 25,000,000 (lives in stock, not including your current one)
Bomb        x  5,000,000 (bombs in stock)

Also, if the stage was FinalB, one additional bonus is added:

Night Bonus x 20,000,000 (every 1/2 hour left before 5:00 am)

Finally, depending on the conditions you played under, the result is multiplied by these modifiers and rounded down to the nearest 10:

4 Initial Lives:    x 0.5
5 Initial Lives:    x 0.2
6 Initial Lives:    x 0.1
7 Initial Lives:    x 0.05
Easy Difficulty:    x 0.5
Normal Difficulty:  x 1.0
Hard Difficulty:    x 1.2
Lunatic Difficulty: x 1.5
Extra Difficulty:   x 2.0

The end result is then added on to your score.

The Time System

Time requirements by level:

Difficulty Stage 1 Stage 2 Stage 3 Stage 4-powerful Stage 4-uncanny Stage 5
Easy 2000 6500 7500 7500 9999 9999
Normal 2500 7200 8500 8500 9999 9999
Hard 2700 7200 8800 8500 9999 9999
Lunatic 3000 7200 8800 8500 9999 9999

Kaguya's last spells have some special rules regarding time. During her last spells, time is added for not clearing each spell card:

Cleared: no time added
Less than half the total time left (15 seconds for the fifth card, 10 seconds otherwise): +0:30 to time
More than half the total time left: +1:00 to time

Also, even if 5:00am is reached during Kaguya's last spells, the player is still considered to have beaten the game; however, the player does not receive a Night Bonus and cannot challenge any remaining last spells.

Endings

The endings depend solely on what the player does and not on the difficulty level the game was set at.

Bad Endings (Endings 9-12)

A Bad Ending is reached if the player runs out of lives during FinalB or if the time of day reaches 5:00 AM (outside of Kaguya's Last Spells).

Normal Endings (Endings 5-8)

Normal Endings are achieved by successfully completing FinalA and defeating Eirin (continues are allowed as long as the timer does not reach 5:00 AM). Failing on Eirin's Last Spell does not matter (although it deprives you of a hefty point bonus).

Good Endings (Endings 1-4)

Good Endings can be seen by successfully completing FinalB and defeating Kaguya (this must be done without continuing). Failing on Kaguya's Last Spells does not matter (although if the timer reaches 5:00 AM, you will be deprived of the chance to challenge any more of Kaguya's Last Spells and you will not be able to get the Night Bonus added to your score, hurting your chances for a very high score).

Glitches

6/7 starting lives bug
Double FPS bug

This is a list of known glitches, bugs or other unusual capabilities that aren't supposed to be part of the original gameplay.

Glitches reported in the full version:

  • Tewi extend glitch: If Tewi's nonspell is cancelled when there are too many bullets on the screen, she will not drop the 1up item. While dodging the pattern, it is almost impossible to tell if this will happen.
  • Stage 4 item bug: If the boss is hit the frame after their second spell ends, it will drop only 17 items instead of 32 items. Hitting a familiar can help prevent this. There may be other ways to prevent it, but this is not well understood at the moment.
  • Stage 6B item bug: If the last fairy is killed right before Eirin enters the screen, it can fail to drop any point items.
  • Alice red shot bug: When using Alice, if you drop the youkai meter below 80%, her shot will stay red. This also very slightly increases damage output.
  • Running time glitch: The running time displayed on the other status list in the game's results section tends to be greatly exaggerated. Every time the game is opened in Windowed mode, it adds the system's uptime to the game's running time.
  • Eirin background error: Both of Eirin's midboss spell cards use Reisen's background instead of Eirin's. This may suggest that Reisen was the stage 6 midboss early in development.
  • Boss hitbox error: During the Extra Stage, when Keine enters, her hitbox is active. This means during the conversation, you can can collide with her and lose a life. This also happens when you collide with Marisa/Reimu in Stage 4 during a conversation. This can be compared to the way Merlin could sometimes kill you in Perfect Cherry Blossom.
  • Spell Practice hitbox errors: On almost every Last Spell, the boss has a larger hitbox in Spell Practice compared to a full game run. This means that in a real run, the spell may take a bit longer to take out. Conversely, in an Extra Stage run, Mokou's phoenix has a hitbox during her final spell, Hourai Doll, but it lacks a hitbox in Spell Practice.
  • 6/7 starting lives bug: In the options menu, if you set the amount of initial lives to six or seven (after unlocking this choice) and then delete your save file, you will still be able to start the game with six or seven lives. This will be the hidden, default selection. Setting the amount of initial lives to another number will lock the choice again (until bad endings are reached three/five times again).
  • Double FPS bug: While using Double FPS setting (which exactly uses Frame Skip 1/2 on config.exe), if the game records the FPS on replay greater than 99.99, the 3rd digit FPS will be showed overtime until next moment. (eg. next spell card, next pattern, etc. but still unexact time).
  • Frame skip bug: The 1/2 Frame skip setting in custom.exe does not work; it does not actually reduce the rendering rate. The 1/3 option does reduce the rendering rate accordingly, so that option should be used instead if the player wants to reduce CPU load. The reduction does not appear to be exactly 1/3, however. Additionally, if vpatch is not used, the FPS display will show 120fps if 1/2 is selected, or 90fps for 1/3.

The following apply to multiple games, including Imperishable Night:

  • Pause menu storage: Pausing the game exactly when the statistics screen is about to open up causes the game to show both the statistics menu and the pause menu at once, giving you control of both simultaneously. In the case of IN however, it can only be done in Practice mode or right before a bad ending on FinalB. Additionally, the game will crash if the player attempts to return to the main menu or retry the stage.
  • Dialogue pause desync: If the game is paused during dialogue, and then unpaused by pressing Z to continue playing, any replay made of such a run will desync on the stage the dialogue unpause was performed on. This can be prevented by unpausing with the Esc key.
  1. Pun on 'youkai' (妖怪), with the 'kai' kanji replaced with the identically-pronounced 回 ('spin').