It's a great start to an endless runner, the art is nice and you have multiple enemy types. I can see a few things that could make it it better. You could add a start screen because when you load up the game you are thrown into the run instantly without warning. I like how it shows you your score after you die and a good thing is the score doesn't continue to go up after you die, but it doesn't reset either. A good way to fix this would be to make it so when hit the respawn button it sets your score back to 0. The collision on the tall blocks is also a bit off as when you run into them they don't do any damage. Great start though! If you continue to work on it I'd love to see how it turns out!