Kyum-Gai: To Be Ninja

Kyum-Gai:To Be Ninja is an arcade game where one has a mission to destroy the head of a sect of ninja's (and others). The game is divided into seven levels, of which the final has a big boss to beat. The game was rather unique in several ways: 1) it required a two button joystick to run well (although, you could use the keyboard for the jump/throw button if you only had a one button joystick), and 2) it was one of the very few arcade quality games that was available for both Disk Extended Basic (RS-DOS or DECB) and OS-9 Level II. It featured digitized sound affects as well, and in the OS-9 version, auto pause if you switched windows, and the ability to multi-task with other programs running in the system.

The original version was by Glen Dahlgren, and the OS-9 port was mostly done by Kevin Darling, and polished up for release by Eddie Kuns.