I did 30, because I just like a lot of junk.
I also start off with a ton of mine drones, since the enemy will generally give you enough time for it.
Some levels are really easy, especially once you start out with a high tech level. You just have to build an IPL to blow up the enemies Center (Takes a two level 4/3?s, maybe a 3/2 and 4/3, but not sure on that). I don't remember if it is level 3 or 4, the one before the Planet Destroyer.
Without the Command Center the enemy is really limited. Usually the ai starts making Battle Centers really fast, but it shouldn't be too much of a problem.
You never get to use the Planet Destroyer in game =\\. Well I guess if the comp takes over that other planet but yea.