It's temple run, but with a blue hedgehog. The boss fights keep it interesting, and the Sonic characters are all good designs, so more motivation to unlock them than in most games of this type, and it's nicely presented - but progression is so slow that it would have to be either a hobby and a money sink, and the difficulty spikes up soon as you reach a certain distance. Good for idly playing - this was my go-to on trains to school as a kid - but in that catergory, there's a million others.