Runs slow, unresponsive controls.
The game itself has a nice concept, but for me it's spoiled by a few things.
First, the game runs rather slowly for me--even on low quality it feels like the character is hopping along on a low-gravity moon walk. This may just be a computer issue on my part, but as the game runs equally slow on high quality as compared to low, I thought it was worth mentioning.
Second, the level timers start way too soon, beginning when the level first opens and not when control is handed off to the player. Due to the first complaint, on average fifteen seconds have passed before I can even start playing the level, sometimes even as many as thirty. Not that I had a chance to begin with, but this does put a bit of a cramp in my chances of ever successfully speedrunning a level.
Third, the controls are slightly unresponsive. In particular, manipulating anything with the 'R' key is impossible to do on a back-to-back basis. For instance, I cannot flip side-by-side switches one after the other. I have to back off of the interaction area before the R key is usable again. Also, hanging onto the edges of walls is somewhat unresponsive as well, allowing the character to fall down a bit before he ever is given the chance to grab on.
Overall, a decent platformer, but it still needs the kinks worked out.