The Binding of Isaac: Spire Edition

Getting started

Open index.html in your browser. The game runs without any server; everything stays on your computer. Language, animations and sound are under ⚙ Settings at the top left of the menu – during a run via the gear at the top right.

1. Pick a file

As in the original, there are three save files. Each file has its own unlocks, its own statistics (runs, wins, deaths, donated coins), its own completion marks and its own boss collection. A run in progress is saved automatically and can be resumed with Continue. More under Save files.

2. Pick a character

On the character note you turn through the characters with ← →. For each character you see hearts, the Isaac stats as ink strokes, starting items and a short description. At first only Isaac is playable – you unlock the others with their own conditions, as in Rebirth (see Characters).

3. Normal, Hard or Extreme

Below the character you pick the difficulty with ↑ ↓ or a click. Hard is blood red and dripping, Extreme dark purple and trembling – details under Hard & Extreme.

4. Completion note & boss collection

To the left of the character hangs its completion note: the character in the middle, the marks of the final bosses around it. Faded marks are still open, black ones were earned on Normal, blood-red framed ones on Hard. Defeated bosses opens the file's boss collection – unknown bosses are just shadows. The Collection next to it shows every item, trinket, card and tarot card you found and every enemy you met. See Bosses & marks.

A run

A run leads through six chapters. Each chapter is a map of rooms leading up to the boss. You can only ever go up – plan your path.

• The map is a sheet of paper that scrolls on its own; when you enter, it jumps to your room.
• You can enter the glowing rooms above you. The boss stays a ? until you enter its room – then a short boss intro follows, as in the original (any key skips it).
• The sidebar on the right (room name, legend) can be collapsed completely with ▸, the legend on its own as well.
• After the chapter boss you fall through the trapdoor and heal 20% of your heart containers (Hard: 15%, Extreme: 8%).

Rooms

From chapter 2 on, treasure rooms are locked with a key. Curse rooms cost half a heart to enter. An event room stays a ? until you enter it.

Secret rooms

After every room you discover a secret room of the floor with a 10% chance and a super secret room with 2% (at most one of each per floor). Opening one costs a bomb. Then you stand in the cave from Rebirth: the loot lies on the floor and is collected one piece at a time – whatever stays behind is gone. The super secret room holds an item from the treasure, boss, devil or angel pool – or lots of hearts. The pill "I Can See Forever!" and the Blue Map reveal the secret rooms for sure.

Floors & paths

Each chapter has two variants, as in Rebirth. From chapter 3 on, the fixed chapter boss waits at the end; the other bosses then appear in the elite rooms.

The way down

• Mom (chapter 3) lets you choose between The Polaroid and The Negative.
• Fixed boss drops as in Rebirth – these items only come from here, never from a room or shop: Famine, Pestilence, War and Death → Cube of Meat or Ball of Bandages (the first drop decides which one it stays for the run; every further copy raises it one level – from level 3 it becomes Meat Boy or Bandage Girl, level 4 is the maximum) · Headless Horseman → A Pony · Conquest → White Pony · Steven → Steven · Krampus → A Lump of Coal or Head of Krampus · Uriel/Gabriel → the next Key Piece; once you have both, a random angel item.
• After Mom's Heart / It Lives you choose: the trapdoor to Sheol (Satan) or the beam of light into the Cathedral (Isaac).
• On the floor The Chest, every normal fight drops an item (golden chest, otherwise treasure room) instead of coins and pickups.
• After Satan you only go on with The Negative into the Dark Room to the Lamb, after Isaac only with The Polaroid into The Chest to ???. Without the matching item, the run is won there.
• If you hold both key pieces (angel rooms) after the Lamb or ???, you open the door to Mega Satan.

Angels & devils

After a chapter boss (up to chapter 4) a door may open. The chance is put together as in the original:

• Base chance 1%, floor without damage +99%, boss without damage +35%, plus items (e.g. Black Candle +15%, Book of Belial, Goat Head = always).
• If the last door appeared 1 or 2 floors ago, the chance only counts 25% or 50%.
• The first door of a run is always a devil room. After that a coin flip decides (beggar donations help) – once you have made a devil deal, you see no more angel rooms. The display in the HUD shows the current odds.
• Devil room: items cost 1–2 heart containers. If your red containers aren't enough, the deal costs 3 Soul Hearts; The Lost gets it for free. Sometimes Krampus or The Fallen guards the room (15%) – then you have to fight; the door stays shut until he is beaten.
• Angel room: you may take one gift, the rest disappears. A bomb on the statue summons Uriel or Gabriel – every defeated angel drops the next key piece, and once you have both, a random angel item.

Combat

Fights are turn-based. You draw cards (Isaac: 5, from shot speed), have Energy (Isaac: 3, the blue tear – from tears) and play cards until your Energy runs out. Then End turn – the enemies act and your hand goes to the discard pile.

Stats

Your combat stats are at the top of the HUD. Hover over one to open a note with its exact sources (character, items, pills, fight). Next to your hearts, ×3 shows how many extra lives you have left (1up!, Dead Cat, Ankh …); ? means there are lives based on chance too, like Guppy's Collar.

Tears → Energy

2.73 tears = 3 Energy, ±1 per 0.8
How fast your character cries sets your Energy per turn. A tears-up item usually gives +0.5 – two of them bring 1 more Energy. Azazel (1.90) only has 2 Energy. The pill Tears Up/Down changes the value by 0.4 for good. The power card Tears Up! and the Battery add +1 Energy directly on top.

Shot speed → cards

1.00 = 5 cards, ±1 per 0.3
How fast your tears fly sets how many cards you draw at the start of a turn. Samson (1.31) draws 6. Shot speed items give +0.16 to +0.5. The power card The Battery adds +1 card directly on top (plus +1 Energy).

Strength

Damage = card value × Strength
Strength is your character's damage stat (Isaac 3.5) plus damage-up items. A Tear with value 2 deals 7 damage at 3.5 Strength. Tear cards also get flat tear bonuses.

Dexterity

From your character's speed: Dexterity = (speed − 1) × 5
Every Block card gives that much more (or less) Block.

Luck

Every point shifts 3% of the card odds from Common to Rare/Epic/Legendary, raises the pickup chance after fights (40% + 5% per luck) and the crit chance by 2%.

💥

Crit

5% + 2% per luck + items
A critical hit deals double damage ("CRITICAL!"). Tough Love gives tears +25%.

Your character's range applies on the first turn: short range = 1 card less, long range = 1 more. Flight gives 20% dodge (see Flight).

Flight

You fly if your character flies (Azazel, The Lost), if you have transformed into Guppy, Beelzebub, Seraphim or Leviathan, if you own a flight item () or carry a pony as your active item. Flight only counts once – two flight items don't fly twice.

• +20% dodge in fights (60% at most together with other dodge items).
• Spikes and pits in ❓ events can't hurt you – you simply float over them.
• Some choices in events are flying only (blue, with wings).
• In fights your character floats above its shadow; the top bar says "flying".

Familiars

Familiar items appear next to Isaac in fights: followers hop in a small group to his right, orbitals circle around him. Hover over one to see what it does.

As in the original, some familiars catch projectiles – attacks from enemies that shoot (Clotty, Pooter, Gusher …). Bites, charges and lasers get through. The Punching Bag, on the other hand, draws every attack. Each familiar rolls on its own, only after dodging. Whoever caught something flashes white; Dry Baby then triggers the Necronomicon with a 33% chance.

Blue flies

As in Rebirth, blue flies stay with Isaac – even from fight to fight (12 at most, counted in the top bar). At the end of your turn each one dives at a random enemy and deals double tear damage (2×💪), then it is gone. Until then they catch projectiles: 10% per fly, 50% at most, and the fly dies doing so. You get flies from Guppy (every tear hit), Mulligan (20% per hit), Infestation (1–3 when you are hit), Guppy's Head (2–4), dark blue champions (3 on death), Beelzebub (enemy flies switch sides with a 50% chance) and the Blue Flies card. Hive Mind doubles their damage.

Hearts

One heart is 20 HP, half a heart 10 HP – the row of hearts shows them as in the original.

Red hearts – your heart containers, can be healed.

Soul Hearts – used up first.

Black Hearts – burst when lost and hit all enemies (8 + 4 × chapter).

Eternal Heart – if you survive the floor with it, it becomes a heart container.

??? only carries Soul Hearts, The Lost none at all: a single hit through your Block is fatal. Extra lives (1up!, Ankh, Dead Cat, Lazarus' Rags …) let you get back up.

Status effects

Powers

Cards

Every character starts with five Tears, four Ducks and one starter card of their own. Each character also has two stronger cards only they can find; the type line shows who a card belongs to. After fights you pick one of three new cards (or none).

Melee and ranged

Every attack shows on its type line how it hits: Melee (Headbutt, knife, heel, Guillotine …) gets the melee bonuses of Aries, Leo, Samson's Chains and Thunder Thighs. Ranged (throws, bombs, flies, projectiles) does not. Ranged · Tear are tear cards – they get all tear bonuses.

Rarity

The border and the gem in the bottom right show the rarity. Bosses only pay out Epic and Legendary.

Upgrading

In the bed ("Dream of a card") or in the shop (25¢, then +15¢ each time, once per shop) you upgrade a card. First you see a preview – before → after – and only then confirm. Upgraded cards have a green title and a "+".

• Attacks: +40% of the card value (at least +0.5)
• Block: +35% (at least +2) · Heal: +40% (at least +2)
• Status effects, Strength, draw, bombs: +1 · familiars: +2 · coins: +2 · Soul/Black Hearts: +½ heart
• If none of that makes it better, the card costs 1 Energy less – or loses Exhaust if it already costs 0.

Removing

In the shop you cut a card out of your deck for 30¢ (then +20¢ each time, once per shop). At least 5 cards remain.

The D6

Isaac's D6 doesn't reroll your hand – after a fight it rerolls the card choice or the item, also in the treasure room and the secret room.

All cards

Characters

The stats come from Rebirth. Damage becomes Strength, speed becomes Dexterity, range applies on the first turn. Every character has its own unlock condition, as in Rebirth – it is shown on its card here and, for locked characters, on the character select. Conditions apply per file; done is done, even mid-run.

Items

All items from Rebirth, translated into the card game. Passive items work permanently, active ones charge up through fights. Hover over an item in the game to see its info note with quality and transformation sets.

• Quality 0–4 (★): better items are rarer.
• Pools as in the original: treasure room, boss, shop, devil, angel, secret room, library, curse …
• The items Blue Map, There's Options, Black Candle, Red Candle, The Candle and Stop Watch only appear once you have donated enough at the donation machine (see Shop).
• Unlocking as in Rebirth: items start locked and don't appear anywhere – not in rooms, shops, boss drops or for Eden. The conditions come from Rebirth: final bosses with a specific character (Satan as Isaac → Mom's Knife), Mom's Heart several times, chapters, bosses, transformations … There is no Boss Rush – its items depend on the character's Mom's Heart mark. Isaac only starts with the D6 once ??? has defeated Isaac; without The Polaroid/The Negative (Isaac or Satan 5 times) the run ends after chapter 5. Secrets on the character select shows how far you are; a big note announces every unlock. The "locked" filter below shows all of them with their condition.
• Items are never taken without asking: on the reward screen, pedestal items and boss loot have a Take button, and random items from beggars, chests or events come with a Take / Leave it note.

Costumes

As in the original, your character's look changes with its items: The Halo adds a halo, Mom's Wig red hair, Spoon Bender a spoon on the forehead … later items are drawn on top. items have a costume. Costumes that recolor almost the whole body (e.g. Brimstone) only fit Isaac himself.

All items

Transformations

Collect three different items from one set and your character transforms – as in Rebirth. Every item counts as soon as you have picked it up once in the run; you don't have to keep it (swapped active items or ones lost to the D4 count, too). For Adult and Stompy, certain pills count. The button at the top right of the HUD shows progress and finished transformations.

Enemies & champions

Every floor has its own enemies from Rebirth. The intent above an enemy shows what it is about to do: attack (with damage, ×hits if any), Block, Strength, weakening, calling reinforcements (with the summoned enemy and count), healing, stealing coins or exploding. All enemies get stronger with every chapter (+12% health, +8% damage per chapter after the first), enemies from earlier chapters even more (+30% health, +25% damage per chapter). Bosses have +20% health, mini-bosses +15% health and damage.

Obstacles like Stone Grimace are invulnerable and disappear once all other enemies are defeated.

Champions

As in Rebirth, a normal enemy can appear as a colored champion: tinted, 15% bigger and with a special effect. A "Champion" chip below the enemy explains on hover what it can do. After the fight it drops its pickup.

Chance: per enemy – Champion Belt +15%. Rare colors only appear from chapter 3 (Depths), yellow from chapter 2.

Hard & Extreme

On the character select you pick the difficulty with ↑ ↓ or a click. Hard is Rebirth's hard mode, Extreme a level of its own above it.

In the boss collection, wins carry the "hard" or "extreme" seal; during a run the HUD shows the difficulty. A higher mark replaces the lower one – an Extreme win also counts for Hard.

Bosses & completion marks

Every boss you defeat goes into your file's boss collection (character select → "Defeated bosses"). The final bosses also give a mark on the character's note – on Hard the red version, which replaces a normal one:

New marks are announced by a strip at the bottom of the screen ("Done!"). Unlocks – characters, items, trinkets, donation milestones – are announced by a big note in the middle of the screen, as in Isaac.

Shop & donations

The shop looks like the original: wooden floor, two flickering fireplaces, the shopkeeper dangling from his rope. The wares lie on the floor with their ¢ price.

• Every floor has exactly one shop – usually on a room many paths lead through.
• Greed like in the original: the first time you enter, there's a 1/3 chance (a bit more with over 20 coins) that Greed waits in the shop – a mini-boss fight. Once beaten he drops 7 coins or (25%) Steam Sale, and then the shop is open as usual. After the first Greed, the next one is Super Greed, and after that none. If you've already beaten a deadly sin on the floor, he stays away.
• Top: an item and pickups (heart, bomb, key, pill or tarot card).
• Bottom: three cards, to their left the card with a green arrow (upgrade), to their right the torn card (remove).
• Red prices are ones you can't afford right now. You leave the shop through the door at the bottom (▼).

Upgrade a card – with preview

Remove a card

The donation machine

A click on the machine donates 1¢. The three wheels show the total, which counts for the whole file across all runs. Every coin jams the machine for the rest of the run with a 5% chance (red ✕) and gives +1 luck with 2%. The 1000th coin blows it up: the counter drops to 0 and 12 dimes (120¢) fly out.

Bed & events

Isaac's bed

• Sleep: heals 20% of your heart containers (Hard: 15%, Extreme: 8%).
• Dream of a card: upgrade a card, with preview.
• Look under the bed: two random pickups.

Event rooms

Pills

Your pocket holds 3 pills or tarot cards combined (Little Baggy: 5). All pills from Rebirth are in: as there, each run has 9 colors, and which color has which effect is reshuffled – you only know after the first swallow. You take pills during fights. Some count towards the Adult and Stompy transformations. If your pocket is full, click a pill or card in the HUD at the top: there you can drop it (it will be gone) or use it right away.

Tarot cards

The 22 tarot cards from Rebirth sit in your pocket like pills and work once. You find them as pickups, after fights and sometimes in the shop; the trinket Ace of Spades brings more. Click the card in the combat bar to use it; clicking it in the HUD opens a note with “Use” and “Drop”. Teleport cards only work on the map, combat cards only in a fight – a card that doesn't fit right now is grayed out and stays in your pocket.

Trinkets

All trinkets from Rebirth. You carry one trinket in a slot of its own next to the items – only Mom's Purse gives a second one. If you find one while the slot is full, a note asks what to leave behind. Click the trinket in the HUD to view it and (outside of fights) drop it; Tick sticks. Trinkets are rare – after fights, more often from mini-bosses and in secret rooms, or as a pickup. Some have to be unlocked first, as in Rebirth (see Secrets on the character select).

Save files

• Three files, each with unlocks, statistics, donation total, completion marks and boss collection.
• The run saves itself after every action. In a fight, the state from the start of the fight is saved – if you continue, the room starts over.
• The door at the top right of the HUD saves and takes you back to the menu.
• A new run overwrites the saved one (as in the original).
• Deleting: "✕ delete" on the file, then confirm "Really delete?".
• Death note: when a run ends, a note like in Isaac shows your character, who killed you (with a picture – or spikes, poison, your own hand), location and difficulty, and every item and trinket you collected. After a win it shows the last boss you defeated.
• History: on the character select, "History" shows the last 30 runs of the file – character, result, floor, cause of death, number of items – and at the top wins/runs and the furthest floor per character.
• Back up: "⤓ Back up" downloads the file as a .json to your device – with unlocks, statistics and the run in progress.
• Load: "⤒ Load" (or "⤒ Load backup" on empty files) reads such a backup back in. If the file already holds a save, the game first asks "Overwrite?". That's also how you take your progress from your PC to your phone.
• Login (optional): if the game runs via tools\serve.ps1, the file screen shows "👤 Log in". You create an account with an email address and password (at least 8 characters) – the address is only your login name, no emails are sent. With an account, your three files are also stored on the server – your phone and PC then share the same saves. Every change is uploaded after a second or two, and opening the file screen fetches anything new from the server. The newer version of each file wins. The first time you log in on a device with saves of its own, the game asks which ones to keep. "Log out" leaves the files on the device. Without the server (e.g. opening index.html directly) there is no login.

Controls

Everywhere: hovering with the mouse opens an info note – for items, stats, hearts, champions, wares, marks and bosses. On a phone: long-press; the next tap closes it.

⚙ Settings (top left on the menu sheets, during a run the gear at the top right): Language Deutsch · English. Animations: Full · Fast (every effect half as long) · Off (attacks, card flights and the boss intro are skipped, nothing floats or pulses). If "Reduce motion" is on in your system, it is always "Off".

Sound (also there): short effects for tears, hits, block, pickups, items, doors, explosions, lasers, the boss intro, unlocks, death and victory. They are generated in the browser – these are not the original sounds from Isaac.

Workshop

For tinkerers: how the game is built and where to change things. There is no build step – just edit files and reload the page. Code comments are in German.

Tools (tools/)

Run in the folder deck-of-tears: powershell -ExecutionPolicy Bypass -File tools\<name>.ps1. Everything is loaded from the Isaac wiki for private use only.

Tests (tests/)

About 50 tests play the real game in an invisible browser (Edge or Chrome) – fights, items, unlocks, saving, English … All at once: powershell -ExecutionPolicy Bypass -File tests\run-tests.ps1 (single ones with -Only lvtest,savebak). Screenshots of a scene, also at phone width: tests\tools\shot.ps1 -Scene scenes\fight.js -W 390 -H 844. More in tests/README.md.

Common changes

• New card: build it in the editor and import it, or add it to CARD_DATA in data.js. The "+" version is created automatically. Its English name goes into EN.cards in lang-en.js.
• Change an item's effect: items.js, entry ITEM_FX.<id> (number fields like str, dex, luck, crit or hooks like onTurn, onKill); English text in EN.items.
• Adjust a champion: enemies.js, CHAMPIONS (weight, chapter, health/damage, drop, color); chances in CHAMPION_CHANCE.
• Hard / Extreme: all values in MODES in game.js, champion chances in CHAMPION_CHANCE (enemies.js).
• Donation milestones: DONATION_UNLOCKS in game.js.
• Base values: crit BASE_CRIT (game.js), heart size HEART and rarities CARD_RARITIES (data.js).

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