A game engine for the classic arcade space shooter games. Currently, I'm basing it off a Space Invaders-style classic called Space Junkie. Version 1 will have one-dimensional ship movement, and enemies will only appear at the beginning of each level. By version 2, I hope to have two-dimensional movement and scrolling levels.
This system will be free to use, no permission or credit required.
Here's an untested link to play the original Space Junkies game: http://www.oldschooldos.com/spacejunkie.php