In this game you play as Penta (short for Pentaro) the penguin, who is trying to capture the heart of Penko. But the problem is, Penta is too fat! Ginji, Penko's current boyfriend, sends his goons out to stop you by throwing food at you! So you must avoid or destroy his goons, collect Fat-B-Gone, and make it to the end of the level in time not to mention you must be thin enough.
Yume Penguin Monogatari is a platform game in which you must help Penta lose weight. As Penta, you can move faster and jump higher when you're thinner, you also have different attacks at every level... er... shape. When you're chubby, you jump into the air and belly-flop your opponents, when you're normal, you kick things, and when you're thin, you shoot things.