A fairly simple concept, and umm, well, I'll list out the bad before the good (sorry in advance).
* No quit button (or retry button after you fail. I had to alt-F4 out of the game and launch it again)
* No death plane (I uhh, fell through a hold and randomly moved until I got the lose screen)
* The character feels *very* slippy
* The terrain doesn't really match (you can go up and down irregular 'steps' and seemingly just ignore them)
* I uhh, hadn't realized at first that I had to collect the coins. It took me falling down and being forced the examine the level to realize that there were collectibles (I totally ran straight towards the monster thinking it was a cave that I had to enter, only to fall down...).
OK, so, other than all that:
Great art! It's always an extra challenge to go 3D in a game jam, and the art shows effort and a unique style!
I'm gonna not say much about the gameplay cause it's really short and very simplistic. Some sort of obstacles/abilities to get past the obstacles would be needed to make it a challenge.
It's a good base to work off of, but feels more like a prototype than anything else.
Lastly, sorry if you feel like I'm being very harsh on you. It's a game jam, so not everything can be perfect (or even close to it). I'm trying to give criticism by pointing out everything that I found wrong so you can do better next time/places to improve on this game. Congrats on actually making something at all!