It's a very small, simple game. Can be addicting if you want to beat high scores.
Coins frequently spawn at gaps, impossible to collect without losing a heart.
Speed increases in steps, with altitude 50, 150, 250, ... but this is not explained in the game and comes kind of unexpected when you first start playing.
Music fits the game, but I'm missing credits. Did you make the music yourself, if not: who did?