Really nice concept. The controls didn't feel frustrating for me as I'm pretty used to mouse-only games. That said, the difficulty seemed a bit arbitrary at times. Sometimes I died almost inmediately due to a huge swarm of pterosaurus spawning all at once.
Also, it took me a few tries to understand what was going on and where my spikes were. A simple image or short tutorial would be really helpful for first-time players.
I think adding a high score marker of sorts based on survival time, height reached or something similar could be an awesome addition to keep players playing and coming back to beat their high score.
(Played on Google Chrome)