A modern, MIT‑licensed reinterpretation of the classic Game Genie — rebuilt for single‑player game enhancement, save‑file patching, and sandbox modifiers.
GameGenie‑X brings the spirit of the original Game Genie into the modern era — but instead of modifying ROM bytes on a cartridge bus, GameGenie‑X applies safe, offline, single‑player patches to:
- save files
- configuration files
- memory snapshots
- sandbox environments
Users enter short GameGenie‑X Codes, which decode into deterministic patches applied through a typed, safety‑checked patch engine.
No cheating in online modes.
No exploits.
Just fun.
MIT license — just like the old days.
GameGenie‑X v2 is a complete architectural upgrade.
It introduces a typed patch engine, profile system, CLI, preview mode, sandbox emulator, fuzz testing, and cross‑platform CI.
- Patch Engine v2 — typed patches, safety rules, deterministic decoding
- Profile System v2 — JSON‑based game schemas with offsets, fields, and constraints
- Developer Experience v2 — full CLI, interactive shell, preview mode, sandbox emulator
- CI & Quality v2 — cross‑platform matrix, fuzzing, strict linting, 100% docstring coverage
Explore the modules:
- Patch Engine v2
- Profile System v2
- CLI v2
- CI & Quality v2
GameGenie‑X uses a compact, custom [Looks like the result wasn't safe to show. Let's switch things up and try something else!] to encode a 75‑bit payload:
- target type (save, config, memory)
- offset or key‑path
- new value
- optional compare value
- checksum
A code like:
GX7L-9A2Q-M4VZ
decodes into a structured patch object that GameGenie‑X applies safely and predictably.
A B C D E F G H J K L M N P R S T V W X Y Z 2 3 4 5 6 7 8 9
- No 0, 1, O, I (to avoid confusion)
- Each symbol = 5 bits
- Dense, compact, nostalgic
A standard GameGenie‑X code is 15 characters, grouped for readability:
XXXXX-XXXXX-XXXXX
Internally, this encodes:
| Bits | Purpose |
|---|---|
| 4 | Target type |
| 20 | Offset / key‑path |
| 16 | New value |
| 16 | Compare value |
| 15 | Checksum |
F2X9W-7K3PZ-9A4TM
Decodes to:
- Target: Save file
- Offset:
0x001A4C - Compare:
0x0005 - New value:
999 - Checksum: valid
Effect:
Sets player’s potion count to 999 (if current count is 5).
Each supported game includes a JSON profile describing:
- save‑file structure
- offsets
- named fields (HP, XP, gold, etc.)
- safety rules
- patch templates
Profiles live in:
profiles/<game>.json
Profiles are validated at load time and used by the patch engine and CLI.
GameGenie‑X includes a full command‑line interface:
gamegeniex decode <code>
gamegeniex apply <code> <savefile>
gamegeniex preview <code> <profile>
gamegeniex sandbox
gamegeniex shell
Features:
- decode
- apply
- preview
- sandbox
- exit
Preview exactly what a code will do:
- field name
- old → new value
- offset
- compare value
- safety rule results
Perfect for modders and tinkerers.
A virtual save‑file environment for safe testing:
- no risk to real data
- deterministic patch application
- ideal for experimentation
GameGenie‑X v2 includes a fully modern CI pipeline:
- Linux
- macOS
- Windows
- 3.10
- 3.11
- 3.12
- ruff strict mode
- mypy
- bandit
- interrogate (100% docstring coverage)
- fuzz testing (Hypothesis)
- 171 passing tests
- Bring back the magic of Game Genie
- Keep everything offline and single‑player
- Make codes fun, shareable, nostalgic
- Provide a clean, typed, MIT‑licensed toolkit
- Build a modular patch engine that grows over time
MIT License — honoring the spirit of open tinkering.
v2.0.0 — July 18, 2026
Patch Engine v2, Profile System v2, CLI v2, and CI v2 are production‑ready.
Built with architectural guidance from Microsoft Copilot, coding support from Google Jules, and review assistance from ChatGPT Codex.