I thought it was decently fun. It took me a while to figure out what was going, though, and I have a feeling that's contributing to the low scores. At first, it seems to be your typical auto-running game. You go along, clicking to jump (and it seems to work, since the character jumps at the same time), and suddenly you find an obstacle you can't get past. You repeat a few times before you realize you can also click the boxes to get rid of them. Now you're trying to jump by clicking and click the boxes at the same time, which is quite the task...also, you eventually realize you can only jump at the end of platforms, which is weird....then you finally realizing that not only is it auto-running, but auto-*jumping* too! Then the game starts making sense and being fun.
So basically, it can take a while before the game is enjoyable, so if people are confused and give up, they might rate it down before they have the chance to see 90% of the game. A very simple line of text or even a couple arrows could fix this.