Assimilate is a new game out now for classic Mac OS—which is to say Mac OS 9.2.2, released more than 20 years ago.
Assimilate is a Flood-It/Drench-style game where you work on filling the board with one solid color. You only get a certain number of moves to begin with, and each level will give you one less move. Every level is procedurally created at run-time to provide you with the most unique experience every time!
People still use OS9! It's me, I'm people. I just like programming, I like this style of game, and I like giving myself a reason to turn on my iBook or iMac.