The Browsing of Isaac

<div align="center"> <img src="docs/media/banner.webp" alt="The Browsing of Isaac" width="100%">

The Binding of Isaac: Repentance+, playable in a browser tab.

<img src="docs/media/gameplay.webp" alt="A run through the Basement: fights, the treasure room and the boss" width="800"> </div>

This is the real Repentance+ game code, recompiled from the Windows executable to WebAssembly. It's not a remake and not an emulator, so every item, synergy and bug works the way it does on PC.

It runs on desktop and on phones, keeps your saves in the browser, and can install mods from the game's own MODS menu.

On a phone

<p align="center"><img src="docs/media/phones.webp" width="800" alt="Playing upright and sideways on a phone"></p>

There are no extra buttons on screen; you play by touching the game.

Move, shoot	Left thumb, right thumb
Active item, card or pill, bomb	Tap it in the bar under the room
Swap items	Tap the small second item
Drop a card or trinket	Hold it
Map	Tap the minimap, or hold it to peek
Pause	The paper icon next to the map
Menus	Tap a row to pick it, tap it again to choose it; swipe to scroll
Back	The BACK note in the corner, or two fingers
Cutscenes	Tap to skip

Held upright, a pad under the picture also moves through the menus; tap it to choose. Switching to another tab pauses the run.

Vibration follows the game's Rumble option.

On a keyboard

Key
<kbd>W</kbd> <kbd>A</kbd> <kbd>S</kbd> <kbd>D</kbd>	Move
<kbd>←</kbd> <kbd>↑</kbd> <kbd>→</kbd> <kbd>↓</kbd>	Shoot
<kbd>Space</kbd>	Active item
<kbd>Q</kbd>	Card or pill
<kbd>E</kbd>	Bomb
<kbd>Ctrl</kbd>	Swap, hold to drop
<kbd>Tab</kbd>	Map
<kbd>Esc</kbd>	Pause
<kbd>F</kbd>	Fullscreen

On a controller

Plug in a controller (USB or Bluetooth), press any button so the browser sees it, and start the run with it: the game gives player one to whichever device starts the run. Buttons are the Xbox layout, sticks are analog, and rumble follows the game's Rumble option. On the MODS screen, <kbd>X</kbd> opens the mod browser.

<p align="center"><img src="docs/media/menus.webp" width="640" alt="Loading, the title screen and the main menu"></p>

Mods

<p align="center"><img src="docs/media/mods.webp" width="640" alt="Installing External Item Descriptions from the MODS screen, then using it in a run"></p>

Mods from the Steam Workshop run here too, Lua and all. Open the game's MODS screen and click MOD BROWSER (press <kbd>B</kbd>, or tap it on a phone): search the catalogue, read what each mod does, and install it. The game restarts with the mod loaded. A mod you already have can be added from a .zip.

Saves

Saves stay in the browser you play in. EDIT FILE on the file select screen exports a save or imports one, including a .dat save from PC. Deleting a file asks first.

Browsers

Chrome, Edge and other Chromium browsers, on desktop or Android. If your browser can't run it, the page says so.

Building it yourself

You need your own copy of the game; this repository has no game files in it. docs/DEVELOPING.md covers the build.

Star history

<a href="https://www.star-history.com/#chiikabu/the-browsing-of-isaac&Date"> <picture> <source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/svg?repos=chiikabu/the-browsing-of-isaac&type=Date&theme=dark"> <source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/svg?repos=chiikabu/the-browsing-of-isaac&type=Date"> <img alt="Star history" src="https://api.star-history.com/svg?repos=chiikabu/the-browsing-of-isaac&type=Date" width="640"> </picture> </a>

Credits

• Ported by chiikabu.
• The Binding of Isaac: Repentance+ is by Edmund McMillen and Nicalis.
• The loading screen dance is the Specialist dance by dazlex.
• Function signatures from REPENTOGON.

The Binding of Isaac belongs to Nicalis, Inc. and Edmund McMillen. This is a fan project, not affiliated with or endorsed by them.

License

Copyright (C) 2026 chiikabu. This project's code is free software under the GNU General Public License v3.0 or later.

The license covers this project's own work only. It gives no rights to The Binding of Isaac: Repentance+: the game's code, assets and name belong to Nicalis, Inc. and Edmund McMillen, and so does anything recompiled or translated from its executable. REPENTOGON, included as a submodule, keeps its own license (GPL-2.0).