In fact, I could only come up with one major, identifiable problem, and you already know what it is. I'll start with the negative: Super Street Fighter IV 3D Edition, by nature of the 3DS platform, can never have arcade perfect controls (or if it does, it'll be the work of some modder, and not widely available or remotely practical). In an age where companies who used to be known for crappy, cheap replacement controllers see enough demand to produce high-end, expensive arcade sticks, it's damning for a fighting game to be on a platform with no hope of optional Sanwa sticks or clicky buttons.
The 3DS circle pad makes short work of rotation moves like Zangief's spinning piledriver, and fighting game fans have gotten along with the d-pad since the SNES days, but the directional controls are far from arcade quality, and the four-face-button configuration fails to achieve the correct Street Fighter layout, relegating two attack buttons to the shoulders. After a while, I found myself switching between the two inputs for different tasks: d-pad for charge moves, circle pad for rotations.
Capcom's solution sounds hacky, but is brilliant in execution: you can assign macros to four areas of the touch screen. In "lite" mode, these macros can be for things like Ultra Combos and special moves. And the game is different (worse in the hands of jerks, but potentially interesting in the hands of experienced players) when things like charged moves can be pulled off instantaneously in rapid succession. "Pro" mode tones it down, and allows useful macros like "all three punches" or "throw" that help make up for the controller deficiencies. When using "lite" controls, my resolve shattered and I couldn't resist the temptation to spam special moves, but when used by more scrupulous players, or when set to "Pro," it's surprisingly elegant.
The other concession to the handheld format is a necessary loss of graphical detail. The game looks fantastic, especially the character models, but a few corners were cut to squeeze it onto 3DS. Most noticeable are the backgrounds, which are now totally static and composed of a weird mixture of flat sprites and 3D models. One hippo in the Africa stage stares agape forever in increasingly hard-to-believe shock, and a crowd of cardboard standees looks on in delight in the festival stage. Weird, yes, and obvious when using the new "dynamic" view (which puts the camera behind the player, at an angle), but they're stages in a fighting game. Not really a big deal.
But if the stages don't exactly match their console equivalents, the online service does, showing a level of "just working" unprecedented for a Nintendo platform. Here's how well it works: the very first time I started the game, when my first arcade mode match began, I received an online challenge. You can choose matches from online lobbies, specify dynamic 3D or the normal perspective, and even watch online matches with "Channel Live" (though the lobbies were always empty when I tried this). Only once did I experience noticeable lag, and I was exclusively playing against people in Japan.
In effect, Super Street Fighter IV 3D Edition is as good as any portable Street Fighter game can be. The touchscreen implementation, in fact, makes it a little better than that baseline, by adding an exclusive input method that actually works. It's no replacement for a genuine arcade button layout -- and you'll never forget that for a minute -- but it's a unique, and differently effective, way to interact with the game. Plus, it's Street Fighter in your pocket! With online play!
This review is based on the Japanese retail version of Super Street Fighter IV: 3D Edition, purchased by Joystiq.