For a school project we're developing a game that's a little like Conway's game of life, with different organisms taking up slots in the world and then eating each other. I would like to see this take place in a 2d world. Like being able to take starcraft and have zergling and marines play roles. The problem with starcraft is that the whole algorithm would have to be written inside of the game editor, and starcraft isn't free or open source. So is there another engine that is starcraft/warcraft/AOE-ish that can be scripted from outside of the game and is freely available? (I'm asking a lot here I know)