In a recent episode of The 8-Bit Theory, the focus shifts to something both challenging and clever—compressing a Mega65 dungeon crawler into a single screen of BASIC code. The project is part of the “Screen Full of BASIC 2025” competition, where the entire game engine had to fit within the confines of 80×25 lines. The result is a compact, functioning 3D-style dungeon crawler—complete with a compass, walls, spinners, teleports, and tile messages—built entirely in BASIC and running on a MEGA65.
What’s impressive here isn’t just the feat of limitation—it’s how it was pulled off. The developer explains how every line of code was squeezed for efficiency, from storing map data directly in REM statements to clever tricks that avoid negative values to conserve screen space. A single function (P) is used as a universal data reader, sidestepping arrays and maximizing BASIC’s limited resources. The compass, player input, and rendering logic are broken into tight loops, each section designed to reduce overhead without sacrificing function.
Wall drawing is handled through coordinate sets crunched into REM lines, then expanded mathematically at runtime. Even the compass direction and on-screen messages are calculated with character string offsets instead of look-up arrays. Despite its size, the game supports strafing, turning, facing-direction-based teleports, and dynamic message tiles—all while giving the illusion of 3D movement.
It’s not a full game, but it works as a tech demo and coding puzzle, showing how far one can push BASIC when thinking creatively. And if you’re wondering—yes, there’s a more traditional version of this dungeon engine explained in a previous video. But this screen-limited version? It’s a masterclass in micro-optimization.
The developer closes with a nod to the contest organizers and hints at what’s next: a C128-based VDC dungeon crawler for another jam. As with all great experiments, sometimes the point isn’t to make the biggest project—it’s to make the smartest one with the fewest bytes.
