In this game, you control a little baby! The baby crawls through imaginary worlds, made of candy, chocolate, toys, and other things a baby would dream of. It has to traverse those platform levels to defeat or avoid various enemies. The way the baby deals with the enemies is quite unusual: it inflates them. When inflated, the enemies lose control and begin to float, until they finally explode. The baby can use this to its advantage, riding the enemies while they are floating, kicking them to various directions, making them bounce off walls, using them as projectiles to hit other enemies, etc. Such strategies are necessary when dealing with the bosses you encounter. There are various items scattered through the levels, such as milk, which restores your health completely.
The NES version of the game is a re-release. The game was originally made for the Famicom Disk System, an add-on for the NES that allowed players to use special floppy disks to save and load entire games. This version also had slightly different music which used the add-on's extra sound channels.
References to the game
Upa, the main character of this game, was also featured in the Parodius series as a playable ship, and in Wai Wai World 2: SOS!! Paseri Jou (Wai Wai World 2: SOS from Parsley Castle), a Japanese-only all-stars game made by Konami for the Famicom in the early 1990s.