v1.4.0 - Isaac Recomp: The Definitive Edition

[whylurking]

This release is about one thing: making sure the recomp plays exactly like the original Flash game. Every enemy,
boss, item, pill, card and trinket of the three versions was checked against the original, frame by frame. The few
differences found are fixed, and the Switch version feels more responsive in busy rooms.

🔬 Checked against the original, frame by frame

The original game was run side by side with the recomp in Ruffle (an
independent Flash emulator), with the same input, the same random numbers and the same clock. Every enemy, tear,
pickup and Isaac himself were compared on every frame: position, speed, knockback, animation, health.

• Enemies: all of them (72 in the original, 90 in Wrath of the Lamb, 90 in Eternal Edition), alone, in real rooms
  of every floor, and shot until they die.
• Bosses: every boss room of every floor, with its variants (74 + 138 + 138 rooms), fought until the boss dies.
• Items: all of them (132 + 198 + 198), picked up and used in fights, with their active items.
• Pills, cards, runes and trinkets: all of them, pills with several random seeds.
• The high-resolution version itself: the original 800×600 game and the recomp's high-resolution one play
  exactly the same.

Fixed along the way:

• Mom's Knife slowly drifted away from where it is in the original (rotations and sizes are now kept exactly as
  the game sets them).
• When a boss died, the poops in the room broke in a different order than in the original.
• The Hourglass works as in the original again: slowed enemies fire twice per attack and the Widow spawns twice
  the spiders. Version 1.3.0 had "fixed" this, but that is how the original game plays.
• Random runs: the numbers the game shuffles at the start of each floor vary as much as in the original.
• Switch and Android: the game's calculations now give exactly the same results as on PC.

⚡ Less input lag in busy rooms (most noticeable on Switch)

On Switch the controls could feel slightly heavier after the first floor, in rooms with many enemies. The image is
now never shown more than 6 ms behind the game on Switch, the same as on the first floor, and freeing memory no
longer delays the next image. Both can be changed in isaac.ini (max_margin, gc_after_tick); they are added to
your existing isaac.ini automatically, with an explanation.

🔊 Sound

• The game no longer waits for the sound mixer, which helps in busy rooms, especially on Switch.
• The music is no longer the first sound to be cut when too many sounds play at once.
• The chest and Satan sounds in the endings play at their original, lower volume.
• Switch mixes at the console's own 48 kHz.

📁 Switch and Android: same folders as on PC

• Switch: your saves, preload*.txt and performance.txt now go in sd:/switch/isaac/saves/, and the save
  converter comes in sd:/switch/isaac/tools/, as on PC.
• Android: the same files now go in IsaacRecomp/saves/ (in the internal storage).
• The first time 1.4.0 starts, the saves already there (sd:/switch/isaac/, IsaacRecomp/) are copied into
  saves/ automatically. The old files are left where they were: you can delete them once you've checked your
  progress is there.

🖼️ Small touches

• The program has the same icon as the Switch and Android versions (Windows: the .exe and its window; Linux: the
  window).
• The save converter (tools/save_converter.html) shows the current save folders.

📦 Downloads

Platform	File	How to install
Windows (64-bit)	IsaacRecomp_Win64.zip	Extract, put Isaac.exe next to IsaacRecomp.exe, run it
Linux (64-bit)	IsaacRecomp_Linux64.tar.gz	Extract, put Isaac.exe next to isaac, run ./isaac
Android	IsaacRecomp.apk	Install it, create the IsaacRecomp folder at the root of the internal storage, copy Isaac.exe into it
Nintendo Switch	IsaacRecomp_Switch.zip	Copy switch/ to the SD card, put Isaac.exe in sd:/switch/isaac/, launch in application mode (hold R)
Source code	IsaacRecomp_source.zip	See Building from source in the README

Updating from 1.3.x: replace the program files. Your saves and isaac.ini keep working. On Switch, copy the new
switch/ folder over the old one (it now includes saves/ and tools/): your saves are copied into saves/ the
first time the game starts. On Android, just install the new APK: the saves are copied into IsaacRecomp/saves/
the same way.

Full details in README.txt (PC / Android) and README_SWITCH.txt (Switch).

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This discussion was created from the release v1.4.0 - Isaac Recomp: The Definitive Edition.