The first and only shmup game to run in a multitasking environment
Or at least the author himself claimed it was at the time. Miniblast for the Commodore Amiga's Workbench OS by Anders Bjerin, that is, released in 1990. He may have been misinformed, who knows?
"A shoot 'em up game which runs just fine in a multitasking environment. At last you can enjoy a satisfying megablast while you are writing a boring essay. Shoot anything that moves, and if it doesn't move, shoot it anyway. This is version 1.00, binary only."
For anyone wondering about the strange cropping; the window is unavoidably cut off on the right when executed in Workbench 2.0, but is complete under 3.0. The problem with running it via an A1200 with the appropriate version of Workbench is that your chopper is far too fast to be controllable. Hmmf.
You don't really lose much except for the benefit of added draw distance, aiding reaction time.