OpenRecet

An open-source, clean-room-style C reimplementation of the Win32 engine ("Azumanga") behind Recettear: An Item Shop's Tale (EasyGameStation, 2007 / Carpe Fulgur EN, 2010) — aiming at a drop-in replacement for recettear.exe that behaves like the original for people who own a legitimate copy of the game.

This is an educational reverse-engineering and game-preservation project. It ships no game assets, no decompiled binary, and no copyrighted content — you bring your own copy of the game. MIT licensed (our code only; no rights to the original game are granted).

OpenRecet (left) next to the original engine (right), on an opening-prologue iv1_2 dialogue line. The dialogue box, nameplate, character standees, the top HUD (clock / day / money) the engine draws over the live map during iv1_2, and the townsfolk drifting past the back window are reproduced bit-for-bit.

More side-by-sides — each is OpenRecet (left) vs the retail engine (right), captured from the same deterministic input trace:

Free-roaming in the shop: the 3D room (geometry, textures, lighting, window god-rays), the persistent top HUD (clock / day / money), the "Change Camera" hint, Recette, and the townsfolk drifting past the back window are all reproduced 1:1.

The iv1_1 "sigh" effect sprite mid-fade (full-screen cutscene, no HUD); and a zoom on the iv1_2 opening conversation poses (Recette's look-up, Tear's reaction).

In memory of Andrew Dice / @SpaceDrakeCF and Carpe Fulgur.

Status — early, not yet playable

This is early-stage and not playable yet. A real boot path runs (title → new game → the 3D shop interior renders), but large subsystems are unported and there is no end-to-end gameplay. The screenshot above is the kind of milestone that's working today; screenshots here get refreshed on major breakthroughs, so treat them as a high-water mark, not a promise of completeness.

For the actual state of things — what's ported, verified, or untouched, function by function — see the live status pages (these are generated from the source, not hand-maintained marketing):

• docs/STATUS.md — 60-second headline: port-coverage counts and the current front.
• docs/port-ledger.md — per-function port status for all ~2,550 engine functions.
• docs/PROGRESS.md — dated narrative changelog.

At a glance right now: ~14% of the engine's non-thunk functions are touched (a few percent runtime-verified against the original). Once the game is mostly playable this section will turn into a short "known issues" list instead.

How it's verified

Correctness is measured as behavioural parity against the original binary, not guesswork:

• Per-draw Direct3D state traces captured from both the port and retail (via Frida) and diffed draw-call by draw-call — this is how the shop's brightness, window blinds, and god-rays above were pinned to 1:1.
• Call-trace diffing — per-frame function-call sequences compared between port and retail to catch missing or divergent logic.
• Frame captures — port-vs-retail image comparisons at fixed frames.
• 2,900+ host unit tests for the portable decoders and game logic, run under AddressSanitizer + UndefinedBehaviorSanitizer on every C change.

Methodology lives in docs/AGENT-WORKFLOW.md and docs/harness-roadmap.md.

Building & running

You need your own legitimately-owned copy of Recettear — the build ships no assets, and on first run the port reads the game's sound effects out of your own retail recettear.exe and caches them locally (it never redistributes them; see docs/formats/se-pack.md).

nix develop            # dev shell: mingw-w64 32-bit cross compiler + RE toolchain
make -C src            # cross-compiles build/openrecet.exe (+ openrecet-debug.exe)
make -C tests run      # the host unit-test suite

Place the resulting openrecet.exe in your Recettear install folder (alongside recettear.exe, which it reads SE from) and run it. The exact reference binary all of this targets is documented in docs/reference/vendor-exe.md.

Pre-built nightly binaries are published as a rolling nightly pre-release (unsigned; bring your own Recettear).

Repository layout

docs/     design notes, file-format specs, RE findings, status pages
src/      the C reimplementation (cross-compiled with mingw32)
tests/    host unit tests, golden-frame diffs, format-decoder tests
tools/    build/run harness, extractors, Frida capture, CI scripts

Support & how this is made

This project's reverse-engineering and documentation is done entirely by AI (Anthropic's Claude), directed by the maintainer. That's both an honest disclosure and, hopefully, an interesting demonstration of what AI-driven RE can do — the methodology is meant to be reproducible.

If you'd like to support the work: ko-fi.com/lolisamurai. Donations go toward the AI compute that does the work — roughly €240 ≈ one month of intense RE, spread across a few projects in parallel to use the subscription efficiently. Games suggested in donations will be considered as future RE targets.

Legal

OpenRecet is an independent, unofficial project and is not affiliated with or endorsed by EasyGameStation or Carpe Fulgur. It contains none of the original game's assets or code and requires you to own a legitimate copy of Recettear (Steam App ID 70400). All trademarks belong to their respective owners. OpenRecet's own source is released under the MIT license.