I liked the art & music :) The main challenge seems to match rows & keys - arrows are located very differently on the keyboard. (Maybe something like 1-2-3-4 could be better? Dunno.) The speed increase is indeed quite low [IMHO] - I managed to get 441 and was somewhat bored for the first ~200-300 points.

I like the game. The visuals are really nice! 

I think it would have made it a notch better if you would have used premade music (because music is always really hard to make sound good in less than an hour) 
Also this would have opened up the space and time to match the popping of the bubbles to the beat, maybe even the pitch of the music assigned to different arrrow keys. That would have been even more satisfying.

But all in all a really nice game! But for me the music on a lonely train rime home would be less creepy and more kind of cozy (but I get the idea that it can be scary o travel alone in an empty train at night)

In Conclusion: A game with good potential and for being made in 3 hours really nice! Congrats!