Cant go wrong with a dino game ! :)
Not much to say in terms of feedback. It's already pretty well rounded .It looks good, plays well & it even have an oline leaderboard ! (I managed to get #1 :) )
Not sure the fireball add much to the gameplay. I ended up not really using it.
You should add keyboard navigation on your game over screen and put the retry button on first select. It's easier to get the player to go "ok just one more try" if he only need to press space again to launch another run. (for unity you can do that through code With UnityEngine.EventSystems.current.SetSelectedGameObject() and passig it the the GameObject of your button)
Appart from that, really cool game. Great work !