Got Total Annihilation when it first came out. I had just started middle school. I don't remember a thing that i learnt for the next two years because of TA ... and it was worth it. Even now, its potential for complex, hours-long gameplay is unmatched. Just make sure you find a modified A.I. on the internet before you play against a computer. The original A.I. isn't terrible but it doesn't stand up to a decent human player... The new A.I. can actually hold its own. If you can find someone else to play against, this is where TA really shines (Tunngle is your friend).