Nice Premise
As much as I do enjoy side scrollers, this was particularly fun. I enjoyed it very much. However it did get boring somewhat quickly. I would recommend adding some nice fast paced music, to help the players get pumped up. The sounds of just the jumps and the wave crashing got a little boring. I do enjoy the double jump feature and the wings, as it adds a nice assist to the game, but i would have done it a little different. As for the different heights and lengths of the cliffs, possibly you could have added a jump meter? Or a light tap on the spacebar gives you a small jump, and a press down on the spacebar gives you a longer, higher jump. Many times I had jumped and i either fell because the jump wasnt enough, or I over jumped the cliff and fell down the other side. Overall it was a good game, however i give you an 8/10 because of those other faults. I definitely enjoyed it, keep up the good work.