I've played quite a few of these horror walking sims at this point. It's kind of my comfort genre in a way. They're almost never especially good, but are weirdly easy games for me to relax into on stream with friends and play through in a night or two so I do enjoy them in some sense. The Short Message is on the more literal side of the walking sim continuum with the vast majority of the game consisting of walking from room to room and examining things for a file or a scene. The only exception to this is a few brief chase scenes that—while they do involve some form of gameplay—are pretty minor and are over in a flash. The game also has the interesting context of being a two-hour entry into the Silent Hill series, offered as a free game on the PS5. Further, my impression going into it was partially shaped by the fact that even a day into release, I'd already read some pretty negative reviews on it, both as a game, and as to its worthiness of the Silent Hill name. Perhaps because of all this preface and context, I went into it with rock bottom expectations and while some of them panned out, I was actually impressed to see that I didn't totally hate the game and did think some aspects were—dare I say—decent. To be clear, on balance I don't think this is a very good game, but it's no worse than most walking sim horror games. If I could give it an in-between score, I'd probably give it a 2.5 rather than 3, I only round up because it was nice being a little pleasantly surprised.
Note: I would like to express my thoughts on the story and themes without littering the review with spoiler tags so I'll mostly just aim to be vague or speak very broadly about the story elements to avoid spoiling the story, which is most all there is to this kind of game.

First of all the presentation is mostly quite strong, with caveats. The environment aesthetics and atmosphere are quite good. Even though there aren't a ton of different settings given the length of the game, they really do evoke pretty much what I would expect for interior environments in a Silent Hill game with similar map layouts brought to life by rather detailed backgrounds and set pieces. There are some jarring frame drops in the chase scenes, but there's a lot going on with the environments there and at least the imagery is pretty good, including the spooky monster chasing you. The music is fantastic and I feel like Akira Yamaoka's work is scored to the game significantly better than it was in the latter Silent Hill games he was credited for. The only downside on presentation is that the voice-acting is generally not very good and while the live-action scenes are okay, they feel kind of weird juxtaposed with the otherwise quite good realistic graphics.
The story is basically the main draw of the game considering there's very little real gameplay and unfortunately, it's mostly a flop. It's got a good basis in my view, dealing with real world and important issues that frankly most media tends to want to ignore, including ones that go hand in hand with Silent Hill's general themes of guilt, regret, and acceptance. The problem is that it is very clumsily executed with embarrassingly hamfisted storytelling that is all the worse for a game in a series all about the subliminal. I expect a lot of this is due to the fact that the game is so short it doesn't have the time for much subtlety or ambiguity, but it's hard to say if that is the problem or if the writers simply weren't up to the task. Regardless, this issue is greatly exacerbated by the fact the game takes on way too much considering its length. A game this short really needs to stay focused to be satisfying, but it instead hops around a number of subplots, themes, and issues that could've each filled the two hours, given the the space they warrant. I actually like and appreciate most all of these ideas they wanted to explore and think they could've made for compelling stories. But shoving them all together makes everything feel so superficial. For the most part, I don't feel like the game says too much especially "bad" about these topics (other than the implied oversimplification), but that's partially because the game has a hard time saying much of anything at all about any of its themes. I think the story and characters have a lot of potential that is just wasted by its format. That said, there are some moments of the story I found genuinely compelling, they just often feel unearned and out of place mixed in with the rest of the narrative.

The one caveat I will mention on this central problem with the game is that much of Anita's struggles are with a depression-driven self-critical inner monologue that warps her perceptions of herself and others' opinion of her. While much of the self-critical commentary feels so over-the-top and unnatural...sadly, depression's inner monologue can be just that. Often the things depression tells its victims simply are over-the-top exaggerations of real perceptions—when they're not outright falsehoods—that's kind of the problem when they become convincing through one's warped perception. It may come across weird in the medium but frankly making it more subtle would be somewhat inaccurate, at least to many people's experience, my own included, though I certainly don't mean to speak for everyone. However, this excuse still only goes so far and the game definitely goes well-beyond what it really needed to for this aim. The bullying parts stand out as especially clichéd for instance.
I think there's always a debate with a new title in the series as to whether this is really much of a Silent Hill game at all. This is an inevitably subjective assessment considering what that means to different people. To me, I'd say sure it is, many of the themes and setup are there, frankly much more than they were in Homecoming for instance. The gameplay is obviously fairly different but aside from the fact there's no puzzle-solving, it's not way different from Shattered Memories structurally which also had chases in place of combat. The city you are in throughout the game is named "Kettenstadt," which Google translate tells me is German for "Chain City," not a bad moniker for what Silent Hill is for those poor souls who end up there. The otherworld aspects of Kettenstadt also seem to function similarly to how they have with other protagonists. I also liked that, as I read it, the documents about the city's real-world struggles mirrored and paralleled upheavals in Anita's own life, a nod to the idea that the town and the protagonist are intertwined at least according to the view from the inside. The character arc and themes surrounding Anita's repression and cyclical suffering that continue unless and until she reaches acceptance too echo past games, as do the environments littered with rust and decay portrayed in a flavor that matches symbolically Anita's own struggles. At the end of the day, while I do think it's plainly got the trappings of Silent Hill in many ways, the execution is simply too poor otherwise to feel like the full package of what I want to see in the series. At least for me, this doesn't mean it's "not Silent Hill," it just means that it's not the Silent Hill game we want. I'm sure many would disagree and say I "just don't get Silent Hill" to which one can always respond "maybe it's you that doesn't get it" because that's the fun of interpretation! I'm being a little facetious here though. Really, I acknowledge this debate to be fairly subjective and reasonable minds are likely to differ and that's totally fine.
Based on what I've seen from general consensus, this probably wouldn't be welcomed by most people, but I think this could've actually been a really good Silent Hill game had it been expanded into a full 8 or so hour experience with more compelling gameplay, puzzles, multiple settings, writing that's able to take its time with more subtlety, etc. So many of the basic ideas and themes it plays with could make for a really compelling story and the symbols and mythology the game presents would actually be quite cool to see developed further in my opinion. I also feel like the bulk—if not all—of the game's flubs are due in large part from having to cram so much into such a short game, even if some of that was simply a mistake in choosing to address so many separate things. Slower, steadier, and more subtle revelations could've driven home a thoroughly compelling narrative on important issues in a way that would've worked a lot better and been a much more satisfying take on a Silent Hill game for modern times.

This is certainly one of those games where I have surprisingly positive things to say but ultimately feel like there's just too much wrong with the game to consider it "good." It accordingly exceeded my own low expectations, but admittedly not by very much. I don't think it's totally without its merits, but my own opinion is still fairly negative. Whether it "is" a Silent Hill game or not, I don't think it's a very good one. As a free game, I think it's okay and I don't regret my time with it at all. However, I have to question it as a marketing device. Silent Hill: Ascension—a sort of f2p "experience" that was mostly marketing—has been a a flop. This game is clearly also intended to be marketing for the series revitalization—given it's not making money on its own—but is similarly not delivering for most people. Both titles seem to be having the reverse effect and making people more cynical about upcoming games than hyped. I have hope that Silent Hill F and the remake of 2 will at least be enjoyable experiences, regardless of whether they live up to loftier expectations, but I can't say that has anything to do with these teaser-type games so far.
My other Silent Hill reviews:
Silent Hill: Homecoming ★★★
Silent Hill: Shattered Memories ★★★
Silent Hill: Downpour ★★★★