WARNING! Ten year old code base, ahead! :)
I wrote this years ago, as an homage to one of my favorite DOS programs as a kid: Typing Tutor IV. It came with a game called Letter Invaders, which I became obsessed with. So, I tried to recreate it, here, changing out monocrhome graphics for an 8-bit retro feel and porting it to Flash. I also added a few features like power-ups.
I uploaded the game to Kongregate YEARS ago, and you can still play it there, today.
The IBM PC I played it on is long gone, but now, you can play the Dos version or the Apple II version in a WASM-based emulator.