I haven't got the time to post, lately, but here is a quick impression on Spore for mobile phones.
Although I've been struggling with the lack of "Save Game" (I have to play the game from the start every time), I really enjoy one aspect of gameplay:
In order to survive, you must eat smaller creatures and escape bigger ones. As you eat, your character gets bigger and bigger, and there is a point - and that's the part I like - you are not so sure the creature next to yours is prey or predator.
This transition (prey -> predator) is, I believe, rare within the same game level, and most of the cases I remember involves power-ups (as in Pac-man) or some kind of warning, letting the player know that he has changed his role. The "transparent" transition we find in Spore mobile is, I think, much more elegant and interesting all around.