Nice simple game. Congratulation for the first game in this site :).
My suggestions for improvement:
- About the score, I think it feels better if you get 1 point each time successfullly dodging a falling bomb and get 5 points for taking coin.
- The jump mechanism is too risky to be used especially the jump height is very high, which makes it better to not use it at all. Maybe you can reduce the jump height. You even add a bottomless pit hazard to make the jump mechanism have more reason to be used.
- When on "game over" screen, using "space" key for restarting is much efficient than using 'r' since the "space" key itself serves no function in "game over" screen and also the "space" is the action key in the gameplay (the jump button).
- Maybe add space key too to start the game? Same reason on "game over" screen
- Also some music would good.
Good luck if you are planning on more improvement to the game :).