Commodore 64 · 1982 · Commodore
Two mazes, two sets of cat positions, and fifteen rounds that pick between them. Everything on this page is drawn from the bytes in the Source tab: the maze bitmaps at $F370 and $F450, the cat templates at $FE08, and the round tables at $FEDB.
Each maze is 224 bytes: 32 cells across, 56 cells down, one bit per cell, four bytes per row, a set bit is a wall. The game paints a 9 by 9 cell window centred on the rat, two characters per cell, so the pictures below show the mazes as the game would draw them if the screen were big enough: wall cells as the grey $7F glyph on the white play background. Nothing beyond the edge is stored; the game fills it with the yellow star glyph $2A.
Each maze has a template of sixteen cat positions, $FE08 and $FE18 for maze A, $FE28 and $FE38 for maze B, stored in character units, two per cell. A normal round keeps a random eight of the sixteen; a SPEED RUN keeps all sixteen. Cats never move, and they are only ever drawn in the maze window, never on the radar. Cheese is placed at random each round and is not part of the map.
The round counter runs 0 to 14 and wraps, so round 16 plays exactly like round 1. Five fifteen-byte tables decide each round: how many red rats, how often they move, how many cats, whether it is a SPEED RUN, and which maze. The table below is read from those bytes.
Red rat and cat counts are stored minus one; the values shown are what you meet. A SPEED RUN freezes the red rats at their spawn points, gives the round all sixteen cats, and drains TIME twice as fast.