Pretty fun.
Suggestion 1: Add a fuel jet that improves a teensy bit each time you level, to make gameplay more interesting.
Suggestion 2: I see you have a plan to implement increased push power when you level, Instead of that, make it so when you level up, you get increased push defense, that way gameplay is more balanced, and nobody gets thrown 1000 yards into the lava ocean.
I made it to level 30 in less than an hour.