Micro31 is a point pressing version of Galaga, where final score is taken at the end of Stage 31, which is Challenge Stage 8. This completes one full cycle of Challenge Stages, after which the game repeats at the same difficulty. This mode can be played on any difficulty and life settings that were available on the Arcade version of Galaga (Rev B), as well as Fast Fire (add-on chip for Arcade, GalagaDS for MAME, and Class of ’81 with Fast Fire code or equivalent).
The most common settings are 3 lives + 20,000/70,000/70,000 on Rank A/Easy, Normal Fire speed, and are assumed as default if not otherwise noted.
Also goes by: Point Press 31, Single Cycle, 1-cycle, etc