If you're familiar with Gooey from Kirby's Dream Land 3, then you'll find he isn't much different, here. Completely new to life on Popstar, in a world full of light and color, there's a lot for Gooey to learn about the world, the universe, and himself. In a lot of ways, he resembles Charlotte, who is also learning a lot about herself and her place in the world, too. However, Gooey seems to show a bit more awareness in areas where Charlotte seems to be completely clueless, by no fault of her own. Gooey can also speak, as well. The information the both of them get about the world is only as good as the people telling them about it, though, and with the sort of weirdos the extended cast Alternate Universe has, well, you're bound to get some bad advice.
Gooey is a good friend of Kirby, and was able to help Kirby defeat Zero by assisting him in the direct offense against him in the Hyper Zone. Gooey is currently seen as a traitor to the species and not the be taken lightly, especially sense he is able to utilize the copy ability technique (similar to a few other denizens of Popstar, as well as Miracle Matter), but the Dark Matter aren't exactly interested in exacting revenge on the turncoat blob, considering that they don't seem to place a lot of importance on independent Dark Matter.
In fact, despite Gooey's notoriety with his species, they don't actually seem to care. In the story, "It Doesn't Matter", Dark Matter invades Dream Land with some additional help. Kirby and friends convince Gooey to try to reason with Dark Matter, only to have Gooey stay behind and play foosball and goof around with Dark Matter while they annoyed the Mayor. Gooey may be loyal to the side of good, but what can you say? Fam is fam.