Who doesn't like some smooth jazz on a cartoony undead action game? It's an unusual combination that gives a specific signature to the game.
The restart animation is very nice. The parallax detail is a nice addition to the backgrounds.
It has a frustration element to it when I died after reaching far away and had to go all the way back. Have you considered fixing the backtracking? So the player doesn't have to make it all the way to the previous point again. Particullary when dying is inevitable after encountering several red guys.