I like the concept. I'm just not very skilled at games on the computer. I didn't get very far. LOL.  The first time I tried jumping to the top and couldn't figure out where the challenge really  was. Then I read the page and saw I needed to push the rock. So I tried but got stuck pretty quickly. I tried to let it roll back a bit to try and get it over and I lost the rock.... -_-;;;; I literally couldn't find it at all.  Maybe add a button you can click to be sent to the rock, or reset with out admitting "I'm a quitter" for when your rock rolls off to parts unknown.  

The avatar looking so weak and only able to jump incorporates the theme well.  Great job, judging from other comments I'm sure if my gaming skill were higher I could have gotten further. 

This was fun and hilarious at the same time. :D  I loved those moments when I was able to string together a number of well-timed pushes to rocket the rock up the hill, but equally enjoyed the times when I over-jumped the rock and wanted it tumble into oblivion.

I know this is a wonky-controls/physics type of game, but it probably could benefit from some tightened jump mechanics, where you can jump high holding space down or jump slightly to reposition yourself, especially when trying to get through some of the timing/positioning-specific parts of the hill.  Also, I was on a roll (no pun intended) getting the rock up the hill, then somehow my body instantly went to the top of the background object and my head got stuck there.  I was so sad, because that was my best run yet! :D 

It took me 6-7 attempts before I finally got the boulder up the hill................and then I accidentally CHUCKED it completely over the while block at the top!! LOL So then I took one of the smaller rocks and used it to launch myself over the while block to my doom. Frustratingly fun. The kind of game that aggravates you so much that you want to finish it just to spite it. LOL Honestly, that was SUCH a challenge! Deceptively hard!! It was like the ragdoll physics had ragdoll physics!