ZERO PAGE
6502 assembly puzzles with bureaucratic dread.
Artillery unit reports systematic deviation in impact coordinates. Field sensors return raw range data, but atmospheric wind drift introduces consistent offset. Program the correction module.
You are contracted to write low-level microprocessor code for a government program. The puzzles are routine. The narrative is not.
ZERO PAGE is a 6502 assembly puzzle game played in a terminal. Fifteen main missions teach the instruction set, from load and store through bit manipulation to indirect addressing. Six bridge missions pace the second half. Three hidden missions live behind in-game clues that attentive play surfaces.
Each puzzle ships with a briefing and a debrief, both written in the register of the agency you work for. Field ballistics units. Suppression filters. Density scanners. Record processing. The bureaucratic language stays clinical. As the puzzles advance, the tone shifts from reassuring to terse to minimal. Read carefully and you see what the agency does.
Play it in your browser
The free web build runs in any modern browser. The original fifteen main missions, the assembly editor, the memory grid, the 6502 instruction subset, the sandbox. Same engine as the standalone. Keyboard-first; mouse supported.
Sandbox mode
Inside the web build, press S from the title screen or any puzzle to enter sandbox mode. Freeform 6502 outside the campaign, same memory model, no mission tests, no time pressure. Useful for the curious; load whatever you want into the zero page and watch what happens.
The Operator Reference Manual
The build ships with the OPERATOR REFERENCE MANUAL, a six-by-nine PDF in the same voice as the briefings. Instruction set, memory map, mission notes, and the parts that did not survive a contractor audit. Read it here.
| System | What it does |
|---|---|
| 6502 engine | Load and store, arithmetic, branching, bit manipulation, stack ops, indirect addressing — a curated subset of the real MOS 6502 instruction set, tuned for puzzle pacing rather than complete chip emulation. |
| Campaign | 24 missions: 15 main (instruction set teach), 6 bridge (difficulty pacing), 3 hidden (in-game clues, classified-module debriefs). Reference solutions ship for every puzzle. |
| Execution controls | Step one instruction at a time, run until completion, configurable cycle limit per mission. Mission tests with pass/fail feedback. |
| Sandbox | Freeform 6502 outside the campaign. Same engine, no constraints. |
| Save tapes | `.6502` files — plain text, hand-editable. Save your program at any point, reload later. |
| Aesthetic | Phosphor green default; amber, stark white-on-black, and light mode all in Options. Optional CRT bloom, scanlines, vignette. Keyboard-first; mouse supported but not primary. |
| Manual | A six-by-nine PDF written in the same diegetic register as the briefings. Ships with the build and is also linked here. |
Stack
Electron 33 with a Vite + React renderer. TypeScript end-to-end. The 6502 engine is a clean reimplementation, not an off-the-shelf emulator — small enough to verify cycle-accurate, focused on the instruction subset the puzzles actually use. Cross-platform builds for Mac (Intel and Apple Silicon), Linux, and Windows.
Lineage
TIS-100, Shenzhen I/O, EXAPUNKS — Zachtronics-adjacent in shape, but the diegetic register pulls from somewhere else entirely. Period bureaucratic prose, recordkeeping language, the way agencies describe their work to themselves. The phosphor terminal aesthetic borrows from late-80s industrial CRT readouts.
Buy
On itch under Conflict Simulations LLC at $6.99 — conflict-simulations-llc.itch.io/zero-page. Native builds for Mac (Intel and Apple Silicon), Linux. Windows build lands this week.
The free fifteen-puzzle web version of ZERO PAGE has lived on itch
in some form for a while. The standalone is the version I always
wanted to ship: the full twenty-four-mission campaign, the bridge
missions that pace the second half, the three classified modules,
and the manual. Thanks for playing.
— Ray