I love playing as acrobatic characters like this, and I also love this precise but fair kind of challenge!
I certainly have no complaints about the gameplay and design, this is a lot of fun, but I'm sorry to say, this falls a little too far off the Game Boy's specs... You did stick to the 4 colours and certainly seemed to stick to the 8 x 8 pixel grid, but you downscaled an asset and it got rendered at a higher resolution than the rest of the game, you should have probably made a new asset for that diagonally-moving smaller spiky block in the second-to-last trial, nevermind the liberal use of extra BG layers and particle effects, or the inaccurate sound effects...
Don't let my strict adherence to the GB specs disillusion you however, you've got a pretty fun game right here that I gladly played all the way through!