Press any key at the title, answer N to the joystick question, pick a
skill level (Kitten … Alley Cat), then any key to start.
In game: cursor keys move, Alt special action, Esc paws mode,
Ctrl+S sound, Ctrl+R restart.
No emulator library, no WebAssembly. The original 55 KB CAT.EXE runs
on a machine written from scratch in JavaScript — 8086 CPU, CGA card, 8253 timer,
PC speaker, XT keyboard. Two engines share that machine: an interpreter that
decodes each instruction, and a static recompiler that translated the game's
1,524 basic blocks into JavaScript functions ahead of time (~1.65× faster).
Every compiled block is verified against the interpreter for identical registers,
flags and memory writes.
← the remake · DOSBox version