First of all, I'm sorry this post totally slipped under my radar and I'm only replying to it now :(
Secondly, thank you so much! I'm glad to hear that. Hopefully the full game will be even better and with even more catchy tunes. This kind of music is fun to write but I'm wondering if making them too cheery and catchy starts to annoy players. I guess we'll have to see :D
Sure, you can use it.