Here is #1 looser of 4K comption of... 2012?? (can't verify). I failed because I never could squeeze this one into 4k! Anyway, it is a simple 3D-ish maze game. It runs in either 40 or 80 column mode. The scenereo:
You are an electron in the Commodore 128's ROM. Navigate the code to find an RTS instruction that will allow you to escape to the next higher level.
Use a joystick or the keyboard's cursor keys to navigate through the maze and find the escape (an open doorway). Points are based on how long it takes you to find the exit. The mazes are actually generated from the ROM. Tested with original 1985 and updated 1986 ROMs (who knows about custom ROMs?).