A fun little game, not too long so when I died it didn't bug me at all. The art was nice for what it was, I think it'd be nicer if the game was zoomed in more so that it was easier to see :]
I liked that there were more than 3 skulls to collect so, if I was having issues, I could have skipped one (the jump to avoid taking damage from the dog in the first area is real tricky!).
If there was any criticism it'd be that I don't really have a whole lot to say. That said, these game jams are a lot about gaining experience and familiarity with making games. I'm excited to see what you'll make next with this game under your belt!