It's a simple game, but it's not too shabby! I like the way it builds up the tension at the start by slowly tilting the hill as it really sold the speed build up, and I found the act of jumping around to be some good simple fun. Game has a decent assortment of obstacles to contend with, especially the cars which were a big highlight. Bit weird that the game always starts at 300m on the score board: you'd think it would display your previous high score or something. I like the touch that you crashing and sliding down the hill still adds to your score: reminds me of something like Kitten Cannon.
While for the most part I was able to skillfully dodge around obstacles and get the 1000m achievement without much trouble, I did feel like I couldn't trust the game to always build a fair assortment of obstacles, and that really bummed me out and kept me from getting addicted to this game. It just felt like my runs depended on the whims of the games random generation: some runs would have barely any obstacles, while others would practically stack 3 or 4 obstacles on top of each other to form an unwinnable scenario. Still, for a little game jam game, I guess I can't expect you to build some sort of super algorithm to ensure that only fair configurations of obstacles are generated, so I'll accept the bit of fun I had.
As a side note, I did find it a bit disappointing that you didn't even bother creating a different graphic for when Stella jumps: looks so silly for her to stay stock-still when jumping, and lazy considering you did create all sorts of other wonderful graphics for crashing, haha. Oh, and Stella is cute.