Poorly programmed.
This isn't annoying simply because it tries to be. Limbo was the same, and that game was awesome. However, what Limbo didn't do was employ controls that were so unresponsive that it was almost impossible to pull off a jump at the right time and speed, which is especially unforgivable in this game considering just how many of those leaps require pin-point accuracy. Also, just the one track that loops (with about ten minutes of silence in between) and no sound effects is simply amateurish.
Challenge is not an excuse for incompetence. Try harder next time.