Happy Feet for the Game Boy Advance is not very good. The game mostly consists of very basic platforming that's pretty easy. The only real platforming threats are icicles that are easy to avoid and rare bottomless pits. The game is also basically a fetch quest simulator, as almost every person asks you to bring something for them. At least the game has decency to bring you back to the sender once you collect stuff so you don't waste more time getting to them. The game also features swimming mechanics, that are pretty decent, the controls are modern, which means you swim in whatever direction you're holding on the D-Pad. The swimming segments themselves aren't that fun though, you have to locate fish or some other food source and watch out for oxygen and enemies. There are a couple underwater chase sequences that are kinda decent, though I found the last one quite frustrating.

There are also a couple mini-games. Dancing, which is a simple rhythm game where you press buttons or D-Pad directions on-screen. These use actual licensed music that sounds really good. That's impressive, but unfortunately, the mini-game drags on and it's just so basic. The other mini-game is sliding, with autoscrolling sort-of isometric point of view. It's alright, the only issue I have is that sometimes there are narrow paths across pits you gotta follow, and these are marked when they appear, but due to the perspective it can be difficult to discern where.

The graphics are alright, and the original soundtrack is good, as usual. Seriously, I can't praise Shin'en enough.

Overall, a pretty bland licensed game. Aside from impressive sounding licensed tracks, it's nothing special.