Great use of colors. Also the menu animations etc. are amazing. Feels super juicy.
One perhaps counter-intuitive thing was that the lightning powerup made the the knight go faster, while I expected the zap to get bigger. idk. perhasps just my expectation.
The animation of the zap is also really cool.
I think the hitbox for spike detection is perhaps a bit large. It felt a bit unfair sometimes in the falling part with the coins.
Liked the sound effects and music as well.
Otherwise great job! :)