There are different elements in the game screen once you click Play.
The upper left text of the game screen is the score. This basically keeps track and shows you how long you've been playing the game.
The upper right text of the game screen shows the number of coins you've collected so far. The coin multiplier increases accordingly:
Your skill (purchased at the upgrade screen) is displayed on the bottom right of the screen. You can also see here whether it is on cooldown or if it is available for use (Spacebar).
HealthEditOn the lower right portion of the screen, you can see the amount of health you have left. Once this is all gone, you go to the Game Over Screen.
CoinsEditCollect coins to be able to purchase upgrades in the Upgrade Screen.
MeteorsEditAvoid meteors or they will reduce your health. (Unless you have invinsibility or you are protected by a shield).