One of the coolest ideas in the jam, and I'm impressed at how well the network play worked. I didn't have any issues with lag, lost connections, or the other jank that plagued my attempts to play Touhou 19 netplay.
The gameplay is pretty straightforward; it plays like a stage of the regular Touhou games, except co-op. Having lives shared between the players is a decision I'm not sure about, as if there are skill differences between the players, it could make going for a clear kind of annoying. The difficulty is also pretty low, I was able to get through Standard on my first try. Yumeko feels a lot harder than Shinki, even. There is a lower difficulty as well, and a good idea for an update would be to add a Hard or Lunatic difficulty.
Visually the game is fine, except for one major issue. Certain bullets appear *below* the player sprites. I noticed this in particular with the ellipse-shaped bullets on Yumeko. This can make doing tight dodges with these bullets very difficult. An easy fix is to just make sure all bullets are always rendered on top of player sprites.
The audio is very good. An energetic dubstep-type song plays throughout the game, which is good for getting you pumped up and keeping you going. I would have liked grazing sounds; the only indication of a graze is a little 20 that pops up by bullets when you graze them.
The story is practically non-existent. Mai and Shinki go through Makai and shoot up a bunch of fairies, then take on Yumeko and Shinki. I think a little intro cutscene (it could play before connecting, and be skipped) would have gone a long way to making me more invested in what's going on. It would also be a chance to improve the visuals of the game, by having more character art, and also incorporating the LGBT themes better.
The LGBT themes are also very light. Mai and Yuki work together as a team, but there's not really anything that hints at their relationship. They could be lovers, friends, or just temporary allies and the game would still work the same way.
Overall, this was a really cool idea that worked surprisingly well, but felt a little rushed. With some polish it would become something I'd want to try playing with other people I know who are into Touhou gameplay.