MacInvaders09 is a port of Allen Huffman's Invaders 09 to the Mac which should run on nearly any Mac runing macOS 10.10 or later.
MacInvaders09 is a Space Invaders like game where you must shoot down swarms of invading enemies. You can control your ship at the bottom part of the screen by using the left and right arrow keys to maneuver your ship and the spacebar to fire on the oncoming invaders.
Invaders 09 was originally written in 6809 assembly language for the Tandy Color Computer 3 running OS-9 Level 2. I ported it to C on the MM/1 running OS-9 68K sometime around 1995 or so and eventually to the Mac in the early 2000s or so. This means the game has successfully run more or less natively on 5 different platforms - the 6809, 68K, PowerPC, x86 and ARM. This also explains the kind of weird way the bitmaps are drawn to the screen...