First of all, using the story of Sisyfaux instead of a generic "guy chained to a boulder" was a really nice detail!
As the others have commented, the physics feel weird, specially Sisyfaux gliding around the air. I also had a lot of problems trying to roll the boulder down from ramps, since most of the time it would go straight into the air and crashing on the slope instead of rolling.
The game design was pretty neat. Each "zone" had a different little puzzle on it. The art and the music were also a good decision. I think it would benefit greatly from checkpoints.