Hello, I've opinionated a tier list for this game's characters and why I believe such or such character would belong to a particular tier (keep in mind that just anyone, lowest tier characters included, is capable of killing when they scale up tho)
-The Chiyari tier, for the super broken, competion unfriendly ones :
Chiyari : she's got good firepower and more importantly the BEST PvP faculty in the entire game. She's got a very clear gameplan that is to pop her level 3 and follow up with her level 2, and it doesn't seem like there's much counterplay against that here. She lacks defensive tools that other good characters have, but there's not a lot of worry on that side if you can just destroy the opponent before they scale up seriously
The S tier, for the super good ones with high potential for undodgeable nonsense :
Reimu : all around pretty good, she's got good firepower, good level 3, good boss attack, and also the STRONGEST burst damage in the entire game : her level 1 fires 4 piercing projectiles that deal damage for as long as they are in contact but they trail before going off, meaning they deal MASSIVE damage to whatever they're initially on top of, and Reimu's level 2 deals lots of damage and clears bullets over a moderately sized area AND comes together with her level 1 : she can literally kill bosses near-instantaneously
Zanmu : firepower is pretty decent, but is actually not a concern as she's got a level 2 that basically transfroms pretty much everything over a pretty big radius into activated(?) spirits, which pretty much die when sneezed on (the explosions from killing mobs also adds additionnal damage): this means that not only can she conveniently get chains, but she also HARD counter the ex and level 3 spells of characters that sends mobs towards her side of the screen ; she's got a nasty ex and level 3 spell, and the needles(?) she send have quite a bit of staying power and reduce the place your oppinent can move around, the middle sides of the screen aren't safe either as some of the needles can pop around these parts, hit box and all, and can accidentally snipe you there.
-The A+ tier, for the characters that are very good and have tools that makes them even very gooder, so much so that their eventual weaknesses become pretty much neglectible :
Toutetsu : her firepower is, uh, kinda there I guess, but she's got a level 1 that clears bullets and instakill trash mobs at close range, and a level 2 that do pretty much the same thing slightly better. The big eagles she sends adds to the chaos with their bullets and them pretty much counting as big bullets themselves, but the most distinctive trait of Toutetsu is the fact that she can spread her zone INDEFINITELY, which gives her some serious cancer potential as she is capable of farming the bullets shooting mobs sent from the ex of some characters or more importantly farming boss attacks to increase her own gauge : she can spread her zone globally, slow bullets globally, charge her gauge with that global graze, and can clear bullets when in a pinch : solid cancer overall, if she was a pokemon team, she would be a stall team
Kicchou : defensive character like Toutetsu, her level 1 clears bullets over a small area and her level 2 does so twice over a small first then on a bigger area. Her ex and level 3, however, is particularly NASTY : her fat otters do basically EVERYTHING you don't want happening to you : fat and tanky bullets sponges that obstruct your bullets, actually shoot bullets, progressively go down on the screen and can bump into you, and them being slow means they have A LOT of staying power : otterly obnoxious. Only weakness would be her lack of offensive options as she's a defensive character (her level 1 doesn't make mobs go poof quite like Toutetsu, and her firepower, while decent, isn't all that), which means she'll struggle a bit when it comes to building up chain. Only reason I'm not putting her in a lower tier is cuz defense seems valuable in such an hectic game where undodgeable waves is sure to come, and also the fact that her fat otters are super nasty
Enoko : an all around solid character, she is basically a weaker Reimu. She's got good firepower and good spread, she's got a mid ranged charge attacks that deal damage AND clear bullets, her ex and level 3 send traps that obstruct the opponent's movement and can get very ridiculous. Also, her trap sprite having some translucent white means tgat the random snowball bullets can get hidden by them, meaning visibility issues for the oppinent as an unintentionnal bonus ... so yeah, she's got basically everything that's good to have and no real weaknesses
-The A- tier, for characters that are just solid overall :
Orin : an offense focused character with piercing shots. Piercing shots are pretty nice in this game cuz enemies are so TANKY, and the front mobs tank bullets for the sake of their friends behing them : piercing shots are nice cuz they deal even amounts of damage towards clumps of enemies. Her level 1 charge can, uh, be counted as a glorified piercing shot or something but isn't super impressive, and her level 2 feels like an inferior version of Zanmu's level 2. Her greatest strength however has to lie in her ex and her level 3, which is about sending these nasty red vengeful spirits on the other guy's side : these things are EXTREMELY tanky, shoot bullets, and simply freak out and start to pulse when accidentally popped by a zone
Marisa : very vanilla character, laser is decent but ain't all that, ex is correct and gets nasty when lasers start springing EVERYWHERE in the opponent screen when the ex pop everywhere. Her charge attack being an a stationnary piercing laser that reaches the end of the screen instantaneously and deal good damage gives her a relatively comfortable time dealing with bosses and making chains.
Toby's fox Ran : okay ish damage, her level 1 is a burst shot and her level 2 buffs her shots (and even affect her level 1's burst shot). She's very normal on the PvP side of things, with the most distinctive thing probably being the horizontal and vertical bullets from her ex and level 3 as well as big surprise cat from her boss attack.
Suika : correct firepower, bullets from options and Suika come in a V ish pattern but is still very reliable, and the options can awkwardly be repositionned through unfocused movement. Her level 1 recall her options and fire a burst shot in a straight line and her level 2 is an actual focus fire of doom with her options that last quite a bit and deal so much damage that you actually have a chance to shoot down one of Orin's red ghosts. Her ex and level 3 sends mini Suika to handle the dirty work at the other guy's screen, and they are surprisingly tanky. Also her Boss spell being a variant of deep mist labyrinth is not very nice. All in all a pretty solid character that has to be played in a weird way.
Seiran : very vanilla character also, she's got exceptionnal firepower by the standards of this game. She shoots good bullets, shoots a pack of bullets with her level 1, shoots even more bullets with her level 2 (although spread damage everywhere instead of being as compact as her level 1), her ex and level 3 shoots EVEN MORE bullets but on the other side of the screen. Did I also mention that her boss attack has her shooting more bullets ?. Anyway, she shoots bullets and is good at it
-The B tier, for the ordinary mortals that cosplays as youkai, who have some kind of idea and playstyle behind them but are hindered by their firepower (still plenty capable of killing if they manage to scale up tho) :
Hisami : good unfocused damage, but her focus shot has an aiming component : aimed bullets are actually bad in this game cuz they more often than not aim at some random enemy that you're not even facing, meaning less damage towards where you're shooting, and with mobs being as tanky AND surprisingly fast as they are in this game, the damage getting spread out doesn't necessarily pay off if the mobs that got some aimed shots run away. In the suspicious leggplant lady case it's slightly fine as the big zone that spreads from behind her can pop spirits for the aimed shots to feast upon, but other than that her focused shot damage gets spread about unnecessarily. Her ex sends wiggly lasers vines in the opponent's screen, her level 3 firest even more of that about everywhere, and her boss spell has those thing tracking you for a bit. Very high walling potential with this girl, a bit hampered by firepower issues
Biten : a very normal character that tries to pretend they're not vanilla by having fancy direction with her shots and a weird zone. Her zone only pops spirits on its periphery, which may seem bad, but it's actually quite large in exchange and can pop spirits pretty easily. Her level 1 a few waves of spread shot while her level 2 deals damage globally twice. I actually feel like she's supposed to have an easy time building chains and bopping acrivated spirits as part of her playstyle due to the focus on the spread damage plus big zone, but her actual firepower doesn't really allow her to optimaly do just that. She sends, uh, sticks(?) with her ex, and her level 3, despite looking simple, is VERY capable of boxing the opponent and killing. All in all a pretty correct character , only held back by firepower issues
Kurokoma : a very strange character. She's like some kind of a dysfunctionnal frankenstein's monster that's build with various parts that do not all have a proper use. To illustrate she's got an unsafe unfocused speed, secretly making her a slow character that can accelerate as focus is more safe ; she's got some kind of hybrid shot featuring a pretty narrow and weak piercing laser as well as regular bullets, so the lasers don't do much when front mobs tank the regular bullets for the mobs that are behind ; her zone justcdoesn't make any sense since it's too small in both length and reach, and doesn't work together with the piercing lasers she have, both regular and charged ; her level 1 fires piercing lasers in a narrow fanning direction BUT without the regular middle piercing laser for its duration, meaning the need for an awkward repositionning in order to actually get value from this, her level 2 fires more piercing lasers in a fanning direction including the center but still is limited in firepower and the fact that it's a level 2. Only reason she's not in the lower tier is because her ex and level 3 are VERY good, as she sends chonky woofs (who are not good boys btw) to handle business : they're somewhat slow, can change their trajectory , and shoot bullets. She's got a fairly simple boss attack that doesn't do much beside instantaneously getting erased by Kicchou's level 1 (bug ?). I'm actually not sure what's the main idea or the playstyle you're supposed to adopt for her in this game
Tsukasa : yet another victim of low firepower. Her level 1 is actually a bit of a trap as it shoots 3 bullets that fan out for the 4 directions, while her regular shot fires 4 bullets in front of her and in a compact manner (also fires some behind but I don't really see the point). Kinda weird. Her level 2 is also like her level 1 but has a zone expand with it (not sure what's its point. Charging gauge ?). Her ex is more PvP related as it sends a tube that shoots small popcorns (plus some occasionnally moving in a spiraling manner) BUT more importantly make the bullets that come in contact with them bigger : snowball bullets becomes round bullets, round bullets become menthos bullets, menthos bullets become big glow bullets, and big glow bullets are NASTY. She's a bit luck dependent as the effect of the tubes depends on them coming into contact with the various falling bullest or the ones she fires with her level 3 and boss attacks. Her relatively lacking firepower plus weird zone gives her a hard time building chain and bopping spurits tho. Very luck dependent but since bullets are pretty much everywhere, her ability is quite nice, even moreso when she manages to sends multiples ex in one go
Sanae : a victim of weak firepower AND homing bullets. She's got a fast expanding big zone, a level 1 that fires homing bullets around her and a level 2 that fires explosive and powerfull froggy bullets all around : it's pretty clear that she's designed to have an easy time building up chains and bopping spirits. Her ex and level 3 that brings horizontal fat lasers is not bad considering how many can pop up with her ability to build up chain, but her weak firepower plus her aiming really, REALLY make her struggle extra hard on boss attacks
-The C tier, for reasonably weak characters whose strength are hard to play with :
Mamizou : "decent" firepower, her unfocused shot is spread out, her focused shot is narrowed down, her ex, level 3 and boss attacks are more bullets. She actually has the BEST bomb in the game, and her level 2 giving bomb pieces to build bomb with makes it quite clear that bomb is her playstyle. However, her level 2 takes a long time to charge and don't do anything else like firing more bullets like her level 1 : this means that outside of the bombs, Mamizou is a pretty weak character that don't do much when played normally, and even going for the bomb farming playstyle makes her do EVEN LESS as she doesn't fire while charging her level 2. On paper, Mamizou played perfectly according to the bombing playstyle is capable of outressourcing opponents and even turn the table on them when the game turns into a ping-pong game of death, Mamizou might deserve a superior tier, but I think she's a mediocre character until she gets to do what she's best at, and even that she can only do a limited number of time before having to painfully grind for more ressources, which is not helped by the fact that bombing consume the gauge
Aunn : like in the demo, weak bullets, unimpressive ex and level 3 (just fancy looking big bullets), her charged level 1 and 2 don't have much range nor firepower. Aunn actually is the BEST at exploiting invincibility frames with her level 2, but it's the level 3 and 4 (plus opponents screwing up) that decides the game : invincibility frames are nice, but aren't exactly a very comfortable option like bullet erasing abilities. All in all, playing to her strengths make her a high risk BUT no real rewards kind of character. Aunn played to perfection might deserve a better tiering, but I'm really not sure if she can outlast and out nonsense the stronger characters
Nazrin : yet another victim of the weak firepower and aiming shot combination. She's got correct damage, but her focused shot has aiming that can go elsewhere, she's got a powerful burst shot in her level 1, but it's plagued by it's aiming component, even her zone is aimed, which, while useful at times, affects the behavior of her bombs, making them AIMED BOMBS that are UNCONTROLLABLE, easily making them the worst bomb in the game. Her level 2 is quite good at dealing with spirits, INCLUDING the fat and big ones from the beast Matriarchs (it makes them go poof), and her ex is still decent at restricting the place the opponent can move about and block bullets, but the fact of the matter is that there are quite a few characters that have tools not unlike Nazrin's (if not better) without being hampered by her various weaknesses plus slow focused speed.
So yeah, all in all, I'm surprised by the fact that the girls, at large, do have a distinct playstyle and feel despite them being so numerous this time. I'm curious where this game's gonna go in the future. Nowadays there's the yearly Touhou World Cup that works as an avenue for people to compete in Touhou games, be it in the survival or score category. But this game's lack of score and shabby netplay makes me curious to see if there's gonna be a chance for it to be played in a greater community event or something. Also fingers crossed for eventual balance changes.