This is good for a first game! Congratulations on finishing it! I really liked the art and the music/sound effects!
A couple of notes:
The issue with the play button not appearing unless you're in full screen can be solved if you set the canvas to scale with screen size, and set an anchor for the button.
The jump doesn't always trigger for some reason.
A few checkpoints would be nice.
But otherwise this is a good entry!