Fun, simple, and cute! It's very clear what your two mechanics are. I did rage a little bit, but that's part of the fun. Great job overall!
Just a little feedback:
The parallax effect is reversed. The mountains should move the slowest, and the closest layer should move the fastest.
The blue spikes blend into the background and can be hard to see.
If you have keyboard controls for the game, it would be great if they could be used to start the game and navigate the menu as well instead of using both the mouse and keyboard.