Generally good, but needed more playtesting. The amount of the giant rocks in the sky was way too high. You hit one 13/15 runs, which capped the distance at around 3000-5000 from level 3-6, if you were lucky enough not to hit it frontally. Meaning you are stuck grinding. All of which would be fine, if there were any way to quit a run. But there isn't.
I really gave this a fair shot. "Maybe I'm just unlucky." But no. Took away any fun or motivation to finish.
Also some glitches and bugs. But nothing major.
Next time, at least add a pause and restart button. Or something like having spikes instead of the boulders in the sky, which ends the run, similar to the turtle game.