Gravitron

Hostile ships are stealing Earth's water. Your ship hangs over a cloud field that scrolls in eight directions. Gravity pulls you down and the ground is fatal. Flying high (white) you are safe but harmless; flying low (green) you can shoot, refuel and be hit. Shoot three saucers to end a level; their shots sweep toward you, and a saucer is worth the level times the level plus one. Fly low over the F depot to refuel. From level 3 the saucers fly, on levels 3, 7 and so on a gravity ring pulls you, and on levels 4, 8 and so on a red orb roams that you must not meet low. Clearing levels 4, 8 and so on earns a spare ship, up to three.

The rules come from a disassembly of the original machine code and keep its sprite coordinates and pixel collisions; only the drawing is scaled to the ColecoVision screen. The title tune is new.

Controls: either controller. Stick left and right turn the ship through 16 headings, up is thrust, down climbs against gravity, and the button fires.

ColecoVision version credited in the source to Claude (an AI made by Anthropic) for Amy Studio, in Amy, the language by Amy Bienvenu, 2026: a faithful adaptation of the original program. From RUN magazine's 1989 ReRUN Special Issue: original Commodore 64 machine-language program by Charles Orcutt, with graphics by Dan Diamante. This is a modern homebrew adaptation, not a commercial Coleco release.