You control a man in very fetching leotards. You've got to make him backflip. And that's it! Sound easy? Hahahah. Hahah. Hah. No.
No, it is not easy.
Requiring a similar level of timing and "rhythm" to something like, say, QWOP, the whole trick to the game is that you control each aspect of the diver's action, from jump to roll to landing. So what looks easy by the start of the video above will look way more indicative of your eventual performance the longer you watch it.