Oof, tough question! If I had to choose, I'd probably go with Touhou 15: Legacy of Lunatic Kingdom. While it still has that signature bullet-hell fun, a lot of people felt it was kind of a step back in terms of design. The major complaint was the system where you can switch between two different shot types, one of which felt pretty underwhelming, and the "bomb" system was also seen as clunky and unbalanced by many fans.

A lot of people also felt that the difficulty was more artificial than challenging, due to enemies having huge health pools and the game being overly grindy. So while it definitely has its merits and its dedicated fans, it's not exactly the go-to game for a lot of players looking for the best Touhou experience.

But hey, Touhou games usually have a way of winning you over even if they’re not perfect. What do you think? Any particular Touhou game you find weak?