It's a very very short game, but it's still really fun given the capabilities of the original game boy. The upgrades are limited to only fireballs. The enemies aren't too varied. Koopas turn into time bombs after stomping them, which is interesting.
CharcharcharcharcharCharcharcharcharcharCharcharcharcharcharCharcharcharcharcharCharcharcharcharcharCharcharcharcharcharCharcharcharcharcharCharcharcharcharcharCharcharcharcharcharCharcharcharcharchar