The concept is fine, and the music is well suited, but there are a lot of bugs. But you probably already knew that, so there is no use in telling you to focus on them first. But after that, I would think about some issues regarding the interface. For some text you have used a texture, instead of a label, making it render stretched and pixelated. Also the level select is not user friendly. I think everyone who played will accidentally select the bottom right level, whilst the hardest to reach is clearly the tutorial level. That shouldn't be the case. Also, I would look into a music manager. For most game engines there are free scripts/plugins that allow you to easily manage your music, and then it doesn't need to restart on every scene transition.

I hope you had a lot of fun making this, and wish you good luck on any future project!