I am not done with Toradora Portable (TDP), but I have some notes to share. They may contain spoilers, hopefully inoffensive.
TDP is readily available (for now) from retailers like Play-Asia. It is a UMD game for Sony PSP, with all the upsides of convenience balanced with the downsides of a proprietary platform (for example, there is no way to take screenshots, which is just a total garbage policy by Sony).VN weenies often complain about anime adaptations (F/SN fans are among the most vocal). Naturally, crossing the barrier of media requires changes. TDP is uniquely situated by being a derivative in the other direction, and by very closely tied to anime: not just in plot, but also in employing the same cast. I fully approve how the material was handled in the transition.
My pluralism may be helped by the observation that for a supposed cheap tie-in, TDP is really quite amazing. Notice that I am not a complete VN virgin: I dabbed by playing Hourglass of Summer and Starlight. I am no judge of writing, and I can see technical problems in TDP, but I liked it from the start, and the Ami path completely won me over.
Thus far I saw various ends for Taiga, Ami, Sumire, and... Yuri-sensei. The latter is actually a gag end: you get Yuri end where other VN would've had a Bad End. Fail to capture items or navigate dialogs and you are railroaded to it. I did not pursue Taiga end specifically, and received an ok Taiga end by failing Sumire end. Speaking of which, Sumire end has a major path all to itself, with the end that made me cringe at how contrieved it was, as the writers had to reconcile the anime premise with putting Ryuuji into the picture somehow. Fortunately, the main branch and especially Ami washed it away decisively. Ami's True End is just about perfect. It builds up well, it's a little bittersweet, yet hopeful; I would say the story is adult-like. In terms of anime it's close to how Honey and Clover handles it. The dialogue is scintillating to my weaboo ear.
The sound is obviously helped by Toradora's stellar cast, especially Eri Kitamura. I think she shined in the game more for various reasons. For example, Ami actually has a trimodal personality. Two are well-known: Ami-chan and Ami-hime. But there is also The Real Ami, which is not well outlined in the anime. The final gym shed scene may be it, if I recall, but even so no blogger even took a note. In the game though, it is an explicit part of the text, and Eri Kitamura had to capture it. Good job, I say.
Not all parts of the production were so good. In particular, it's possible -- very easy in fact -- for the player to hit story fragments in varying order, but in a couple of places the dialog is not adjusted for that, making a complete hash of the proceedings. In other parts the dialog changes, and in yet other ones writers are careful with expressions. For instance, you may run into Taiga and find that she's bleeding; the subsequent dialog is careful not to deal with the reasons why. The alternative is to talk to someone who explains what happened. All of that is an equivalent of SHAFT's lack of animation: the creators saved on dialog variants.
By the way, not sure if it's a downside, but TDP has no sex of any kind. Actually, not even a kiss (at paths that I followed). On the other hand creators relish in bikinis, even including corresponding filler. Just as in the anime, boys are nipple-less at the pool. It is really dumb, but not a fault of TDP itself, more like Japan's.
The accessibility to Anglophones is an issue that does not loom large in my mind anymore. My wife once watched me play TDP and I interpreted the lines for her (it was not a real synchronous translation because the playback stops after every two sentences). I was surprised how much I was able to interpret that way. Still, I missed quite a bit as well. Fortunately the game is fully voiced (including Ryuuji's lines, although excluding choice selections), so I was able to look kanji up phonetically in my electronic dictionary. I don't know if it is likely for TDP to receive a translation (either official or unofficial), because I do not know anything about the gaming market. Honestly, I even have no idea if Toradora anime by NISA is likely to be a success, what to say about the game.
One last thing I liked about TDP is that it's a real VN. I did not have to suffer through some retarded combat sequences, and the closest the game came to a puzzle was what I call a "mood dialog", when the player selected from a set of 18 questions for protagonist to ask his interlocutor. I watched how Ana-sempai played Lux-Pain and the combat in it was, not to put too fine a point to it, garbage. Why even include it?! TDP did not and it is great.
I just wish there was a Linux port.