I always switched it to god mode, never really "played" the game but played in its sandbox-ness. Carnivorous plant civilization, ho!
Startopia was fun, I wish you could've had more to do outside your station... or make a linked empire of them. The Greys freak me out.
I tried SimLife for about a week but couldn't make it work. I think I'll find it again someday....
Anyone played that Star Wars ecology simulation, where you terraform a moon for the Gungans?http://www.lucaslearning.com/products/gungan.htm
That I'm reccomending a kid's game (Ages 9 and up!!) is embarrasing. There is a "create-a-critter" mode, which I will definately have to check out.