Ippo is a manga/anime that seems to be pretty popular in Japan, sort of like the Japanese take on Rocky where this kid battles his way to the top while singing "Getting strong now! Won't be long now!", or whatever the equivalent of that is in Japanese. Anyway, it obviously recalls the arcade version of Punch-Out in it's appearance, but the gameplay is a lot faster-paced and more sophisticated.
This one's all in Japanese and there's no fan translation at the moment, but it's not too hard for round-eyes to get through. The main bulk of the game is the Tournament where Ippo takes on all the other boxers one by one to become Intercontinental Champion or whatever. Once you've beaten a boxer you unlock them for two-player mode, where you can fight any of the computer opponents you've already beaten.
The game seems overwhelming at first because there's no tutorial, and the very first guy comes out punching at you aggressively. Button B just seems to make you drop your guard, while button A throws out a couple of weak jabs, and it's not immediately obvious how to dodge punches. If you play around with the A button though, you soon find that pressing up throws a fairly powerful uppercut, holding right+A does a body blow, and holding left+A does some ultimate cross combo that if it connects usually plants the foe on the canvas. Usually just by not touching anything at all, you leave the gloves up in front of you and automatically block anything. If you take too many hits in a row without landing a few of your own, though, you can have your guard smashed and be unable to block for awhile. You can do that to the opponents too though, preventing them from turtling by jumping down their throats with aggressive flurries.
Once you figure out how to work the uppercut and cross combo into your rotation, you can pretty much spam those to death to win the first five or six matches with ease. In fact, that's about the only way to do it that I know of, because I couldn't figure out the controls well enough to come up with any other strategies.
This guy is the second challenger ... his little Hurricane Punch thing is kind of cheesy, but he really doesn't do much damage, and you can uppercut him into the ground without too much trouble.
The next two challengers hit a little bit faster and harder, but they're both still susceptible to aggressive uppercuts and crosses. The second faux-Jamaican whitey guy likes to stay out of your range and use his Dhalsim arms or something to hit you from where you can't retaliate, so you have to keep tapping Up to approach him and get him up against the ropes where you can sting like a tree with your brutal blows.
Unfortunately this guy (the Ivan Drago of this game?) is way too powerful to spam the uppercut/cross combo on. He seems to punch continually and every punch of his has priority over everything you do. If you try to block, he just keeps wailing on you and his punches are so powerful that he shatters your guard break with only a combo or two and then plants you on your ass with like two more combos.
As mentioned before once you've beaten a guy in the single player mode, he becomes available for two player or for sparring matches against any other computer guy you've beaten. They all seem to have different punch styles and weaknesses. They also apparently each have special moves, as I saw the computer busting them out repeatedly, but I never figured out how to use them.
Ippo has some problems, but I'm giving it the benefit of the doubt as part of it is the fact that there's no intelligible tutorial to explain how to do everything, and also the possibility of two-player Punch-Out gameplay is very enticing. It's way too easy up until you hit Volg, and then suddenly it becomes way too hard. The gameplay seems pretty button-mashy and random as it is, but maybe there's more refinement to it when you actually understand how everything works. The graphics are pretty impressive for the GBA, and it would be nice to see a translation for this one.
Update 7/2012: So apparently a full fan translation did come out for this at some point. I played about an hour with it and didn't feel the experience was different enough to warrant a full re-review from scratch, since there's barely any story text and having English menus doesn't make the gameplay or sense of timing any less confusing. It's pretty much standard Treasure: impressive visuals and unique structure, but the gameplay can be a real butt and sometimes you feel like you're barely in control of the action.