R-Type Neo · R-Type Plus
R-Type Neo is a personal reverse-engineering study: the 1987 arcade program translated, instruction by instruction, from Irem's NEC V30 to the Neo Geo's Motorola 68000, with everything the game sends to its video chips redrawn through the Neo Geo sprite engine. On top of it run modes the original never had: two-player co-op driven by the original's own player code, Armour, stage select and a Boss Rush with saved rankings. The translator is a Python tool built on Capstone, written with AI assistance and checked frame by frame against the arcade in MAME; only the hot spots are hand-written 68000. It runs in MAME and on a real JAMMA cabinet, and the work continues.
Its companion, R-Type Plus, has a site of its own, and there nothing is translated: the original Irem M72 arcade board's own program is patched in place. About 8 KB of new V30 assembly, hooked into the original code, brings the same modes to the arcade game at its native 384×256, with a run timer on Boss Rush. Both are private and non-commercial; the only thing published is the Plus patcher and its source, under the MIT licence, and no ROMs or game data are distributed.
68000 asmNEC V30Neo Geo MVSIrem M72CapstoneMAMEAI-assisted~21,700 instructions translated22 hand-written routines59.19 Hz