T-rex lack of progress indicator is frustrating. Not at all clear if a smaller 30mi is doing any meaningful damage or if I should be building 50mi+ or if its purely a number of hits and size doesn't matter. Almost gave up after hitting it with 10 or so rocks of various sizes. Luckily the badge made me continue :P
I have to say it is very fun, but I got bored before reaching a finish line. This game would be pretty epic if it had "the usual" upgrade system. I would also pay money for it on my phone if it had that.
I was very frustrated with the controls and none of the options were remotely close to what I wanted. Full customization would be awesome. To me X and C feel backwards on the default controls, too many years of Mario where jump is on the right. :)
I think you should reverse the keys. Seems like C is commonly a support type move while Z is the primary attack. Its much easier to mash on with your index finger vs your ring finger if your keeping all three buttons covered.