If I was going to improve anything on this game it would be a confirmation button for evolving and purchasing.
I have already evolved about 4 or 5 creatures at least one level accidently and bought two extremly expensive and of course useless incubators when I have to put the phone with the game on, in my pocket, for some reason.
For instance, today I was out walking and hunting DNA and saw somebody needed help with their car. I immediately put the phone in my pocket and helped them out. I took my phone out, and was horrified to see I had yet again made an incubator purchase.