Universal Gravitation is based around a story book and its keeper Hongo, who has entrapped Yoshi's Island in a pop-up book. The book consist of six chapters, each of which are guarded by spirits who can help free Yoshi's Island, but you need to fulfil each of the spirit's wishes before they will help.

The objectives range form collecting a certain amount of coins or apples, breaking through walls using swinging balls, getting through levels in a certain amount of time and even shooting yourself through stages using cannons. Each of the objectives range in difficulty, but nothing that will get you stumped for an hour or so, just to get through the level. On completion of each objective you will be given a medal, which you need to complete the level and to move on to the next chapter. The better you do at each level gives you the chance to spin the bonus wheel that allows you to earn more coins.

The spirits are colourful characters and are well designed to the book theme of this game. Also included in the line-up of colourful and sometimes psychotic looking characters is the infamous Nintendo bad boy Bowser. In fact, Bowser is the cause of all this chaos. It was Bowser that Hongo was trying to banish to the pop up book but instead Hongo trapped Bowser and the island. Now Yoshi must also battle Bowser in the final page of the book to free his beloved home.

Universal Gravitation has 40+ levels to go through and on a good day you could possibly do it a few hours or so. Although this may not sound very challenging, it does offer something that you do not see that often - tilt control. Yoshi's Universal Gravitation uses a specially designed cartridge which senses the way the handheld is being held. This allows the gamer to change the environment by simply tilting the GBA or DS. Your whole world can be flipped so you can walk up walls, choose the direction a cannon shoots, roll boulders and move high wire platforms.