I agree, I think the music is really catchy and it fits perfectly in a platformer game !
The intro music is called "Victory!" and was composed, performed, mixed and mastered by Viktor Kraus. If you wanna check out more of his stuff, visit https://www.youtube.com/user/Weltenmaler
The music in levels 5-10 was composed by Chance de la Soul (https://opengameart.org/users/chance-de-la-soul)
By the way, thanks for your feedback, it helps me to be a better videogame designer. i am glad you liked my game!