Funny little game idea. I had some smaller issues with the movement especially using directions (left+right) and jump at same time - sometimes the direction was not taken into account. Maybe just something I need more practice.
Also I got stuck once as I lost different coins which did not respawn as these were not banked so I had not enough to finish the game.
But overall for a first game I think it is a good idea and implementation. Congratz for your first game.