The game is pretty serious and I had fun playing it! The controls are a bit tricky sometimes and I find it hard to do some precision jumps.
I noticed one thing that I don't like and it's the timer on the top-right of the screen. You are already punished by dying a lot, and when you finally reach that checkpoint all your progress is lost again if you run out of time. I don't think it adds anything to the game.
Also, spinning gives you points but I actually don't use it because a) you don't need so many points to complete a level and b) being fast means you are more likely to run into spikes or fall off platforms.