Great game, too easy. I always like these survival vs AI games and this has a lot of good ideas. I would like to see soldiers themselves cost money to rebuild or something. It's all too easy and I'm constantly capped at 40/40.
More buildings would be neat; maybe a wall that can't be passed, buildable elevators, your own ship that can take damage, and other such things.
The options for guns are great, but I didn't end up using most of them because they are unnecessary. Also, it's a case of more expensive = better where it'd be fun to have each one with its own play style.