I didn't think it was too bad, but yeah, the down time between challenges is a no-no. It looks like it would be much more fun if it was multiplayer.
I'm sure the full retail will probably be better. I hope so at least. I remember seeing "this challenge is not in the demo" a lot, so if they had like a challenge at every traffic light that might balance out the game's driving distance better. The actual races are decent, and they took traffic checks out, thank god.
That would be my review of the demo if they didn't take Crash Mode out.
BUT NO CRASH MODE? WHAT THE FUCK. STUNT MODE SUCKS DICK I WANT CRASH MODE BACK.