I think that your games base is decent: It's more or less Happy Wheels or Trials. What I'm trying to figure out is what direction it's going in, because levels seem to range from fun Sonic the Hedgehog style romps to challenging skill testing sequences and generally confusing level design (How in the hell do you get over this wall?)
Drop the dialogue. Or just replace the bears dialogue with stock bear roaring noises. It doesn't service the game in anyway in its current state.
The most fun I had was on the police level. It was a massive difficulty spike, but that's fine, It's a demo. You can iron that out. When I was hitting those grind rails just right and picking up a ton of speed, I was having a blast. I think if you focus on that element, the high octane ridiculous dirt bike game works really well. I think when I'm casually strolling through a level that pretty much plays itself, I'm not getting much from the game. I would introduce the grind rails immediately, because they're so much fun, and it would suck if somebody dropped the game before reaching them.When the game works, it works good. But a lot of the time I feel like what is fun about the game and what the level is trying to do aren't in sync.