The art looks good. The game feels simple.
My opinion:
1.) Just realized you can hold the Up or W button way later to climb as I just kept pressing it like Flappy Bird before. That should be made clear.
2.) I was kinda saddened at the fact that I climbed way up already then the dragon hit me once and now I'm back at the start. Now it became repetitive. Would be nice to get like a reward for getting far but got hit by the dragon (but that's just me)
That's just my opinion. It was an experience, pretty good one at that. Good game.