FAQ 
1) Why does it get really slow sometimes?
This game has high system requirements to run the AI and graphics. Especially in the last arcade mission where there are 4 players. Your best bet is to reduce the quality by pressing the little TV button at the bottom of the game. You can also not build so many non-essential units. You probably need at most 4 supply drones.

2) Why didn't you make this multiplayer?
I want to see how popular the single player is before I dedicate time to making it multiplayer. Its guts are already wired to be a 4 player multiplayer game.

3) Are there any other drones in this game?
Yes there is one drone that is not listed, if you ever make to survival mode by wave 20 you will start seeing hi-speed NUKE drones. Better get them before the hit the mothership!