Such a cute premise! Puts a whole new spin on the typical arrow memorization games.
I agree with cdrch that a gentler difficulty curve would be great. Maybe the early levels could be slower, and with less arrows. Start with one, then two and work the way up!! Also it might be nice if failing a combination would result in the same combination repeating, that would also make the game feel more focused and strategy driven! :)
Oh also, I think enabling full screen would fix the issue with the arrows not working, because what happened with me is that the arrows would control the page scroll instead of the game. You should be able to enable full screen on the game's page in edit mode!
Hopefully that helps you! Congratulations on creating this adorable game in 48 hours!
-Sasha