I finished Cave Story (Doukutsu Monogatari) the other day, LOVED IT!!! That, plus my love of Nyan Cat led to this. I didn't make the sprites or the background though (link below). I didn't make the music either (obviously). I downloaded a midi file for the Nyan Cat tune and put it through my 8-bit plug-in in GarageBand.
I would highly recommend Cave Story to those who havn't played.Link to Official WebsiteLink to Sprites