So I think there are a few chapters out enough of the currently running mangas for me to make an impression. Those include the ones released in Strange Creators in Outer World. So on to the ZUN written ones first:
Cheating Detective Satori
Admittedly my least favorite of the bunch. I am not a big fan of the character designs. It's not outright bad, but it gives a slightly uncanny vibe. The bigger problem is that the background art is mostly just flat. There is nothing interesting to look at, and for a mystery, it doesn't carry much tension. I do like the premise, though, the concept of a cheating detective because she can read minds. At the very least, some of the character interactions are pretty great, and this is the most characterization that Flandre is given, so in that sense, I am glad this got made.
Lotus Eater
An interesting work with a festive mood combined with a low key eeriness. This is accompanied by scenes of dreams/hallucination involving monster attacks that are extremely striking and beautiful to look at. Seriously, some of the paneling/art combo is really cool. The new character here is Okunoda Miyoi, and as in most Touhou character designs, it is pretty good. Her design has a whale motif and it is realized pretty well, and that in your face whale hat is pretty cute. The mystery here is the trouble she is causing, the how and why. A lot of the fun so far is in the party scenes, where the bulk of the character interaction happens. Now, at this point, three of the chapters have the same sort of thing happening, broad structure wise. Hopefully the story eventually change things up.
The next two are the ones released in SCoOW, and really blurs the line between official and fandom created works. If you ask me, I think these are essential works that any Touhou fans should read:
The Shimigami is Rowing Her Boat as Usual
This one is done by Azuma Maya, the same one who did Wild and Horned Hermit! My favorite of them all, this one puts Komachi in an unusual situation. Basically the premise is, what happens when a god gains empathy for human lives? Komachi was one of the highlights of Wild and Horned Hermit, which made her one of my favorite characters, and here AzuMaya takes her character even further. I sort of see her in a new light, or rather, it brought out that aspect of her that was sort of there. As for the art work, it is basically the same as the final stretches of Wild and Horned Hermit, which means it is pretty good. I think her character designs is the part that stands out the most, Somehow when her characters smile, they have a beautiful smiling face.
The Gensokyo of Humans
This one is about an intriguing mystery involving Akyuu. Rumor is going around that she is ill, that her mental faculty is not all there, and so the people around her are keeping her locked up. Involving a bit of human village politics dealing with the whole issue of the reincarnation of Hieda no Are, a whole novel side I haven't seen explored, this and Azuma's work appearing in the official magazine certainly expands on what is possible for derivative works to contribute to the overall canon. Not that "official canon" is important to Touhou. After all, it's Touhou, a property more driven by fandom than any other property. I just find it cool these two works have been allowed to stretch their creative muscles and then displayed prominently by the main Touhou magazine.
Digression aside, the story plays out like a classic mystery, with a dash of spooky ghost story. The mystery itself is really good and moves at a brisk pace. The next chapter should be the reveal. Other than that, there are lots of great character moments involving Akyuu, Kosuzu, Reimu, and Marisa. Reimu and Marisa here are the investigative team, and Reimu plays the eccentric detective. Akyuu is just sassy, randomly reciting the Kojiki from memory to show that no, she has not lost it. And as for Kosuzu, her friendship with Akyuu is the emotional core of the story.
The art is fantastic. It has the best background arts out of these four works. The architecture and sense of place in Gensokyo is fully realized, and the interior rooms are brimming with details. There is also some great use of lighting, with harsh contrasts and delicate shadows used along with some well thought out composition that adds to the uneasy feeling in certain scenes. The character designs are definitely a bit harsher than the usual fare for Touhou doujins, which I think mainly has to do with the way the illustrator used straighter lines, a little less round face designs, light bits of textured shading, and a different eye design, which grounds the characters into this somewhat creepy kind of mood.
So yeah, I think they are all at very least enjoyable, and three of them are fantastic in some ways.