Cell and creature phases are extremely repetitive and boring, IMO. I was satisfied with them for about 10 mins, then after I 'leveled up' a few times, I was like 'man, do I *really* have to do this a bunch more times?'
Just started tribe phase, and it seems like it has more depth, but I only got to play around with it 5 mins last night.
I'm really just looking forward to the space phase.
Oh, one thing that I thought was really well done was the history/progress chart of your creature. Awesome thing to look at, shows deaths, kills, changes in body structure, etc.