This is a very interesting game. But just as everyone said it can get a bit repetitive after a few levels. Adding one or two mechanics that compliment that main mechanics would keep the game engaging. For instant, other lethal hazard like rolling rocks or meteor could increase the depth of the game.
The musics is very intense. However the Wilhelm scream when you die, while funny, it is a bit out of place.
Overall, it is a very nice game. And well done making it in 48 hours.
I imagine this game can be very enjoyable on mobile phones too. Maybe you can consider porting it to the mobile platform as the simple controls allows it to be played easily on phones.