Amoeba

Short:        Clone of Space Invaders
Author:       LateNight Developments
Architecture: m68k-amigaos
Source:       Fish collection

This clone of Space Invaders is one of the best freely redistributable
games for the Amiga to date.  Unlike many commercial games, it even works
correctly in a multitasking environment (by not requiring you to reboot
just to play a game).  Highly recommended!