Bio Miracle Bokutte Upa (NES 1988/1993)

Alright. Okay. So um. Okay in this game, you're a baby. And you crawl around and jump, and you use your rattle as a weapon. And the rattle inflates the enemies into balloons. And you can use the balloned-out enemies as projectiles or platforms. And when you're invincible, you stand upright. And it looks really weird. Also sometimes you have to eat your way through giant cakes.

I don't think there's even anything else to say. Play this shit. It's also available on the Wii Virtual Console, so get it there if you like it.