I’ve thought this floppy just wont boot. I once received it among lots of old DOS 3.2/early 3.3 floppies and could not get it to boot (knew it was 13-sector after looking at it with disk editor) and put it side. Now i just came across it again and give it a try. It did boot. But not everytime.
There seems to be an later 16-sector version of it around as well, which kind of was an suprise.
There were great discussion about the game and the copy protection written by legendary Apple II hacker “HotRod” in Googlegroups at:
The original 13-sector floppy.
Before you get to play the game, you are asked if you (really) need instructions, or if you are uisng game controllers or if you wish to hear the sound effects.
The game itself is pretty basic Invaders-clone shoot-em-up game with pretty amusing enemies that are attacking you. Shoot ’em all!