we love touhou 14, double dealing character! this is the game we started with, because our first touhou headmate Kagerou is in it. We like it because mechanically, it's not too flashy, but the mechanic it does have adds a new layer to the typical touhou thing of learning the stages, where the enemies are, where openings are to take risks, has a really satisfying interplay of risk and reward. if you understand this system you can squeeze a ton of resources out of it, and if you're like me, you'll need them!
it also has batshit patterns and characters, sometimes horribly glitchy in fun ways. some patterns are notorious for being kind of absurd an ask for a beginner, and on lunatic even absurd for a seasoned player. jank hitboxes, being forced to add a new layer of processing between what you see and what you input. but damn, it's rewarding, and it teaches you to use the fuck out of your bombs.
overall, it's not one people talk about much actually! the games people usually talk about are the earliest ones, or the hardest ones. ddc is neither of this honestly. but it's a good play, has a simple but elegant "gimmick", and teaches a lot of the skills you can rely on to succeed in similar touhou games.
(and one more thing, it has proper practice options. early touhou games don't, and that makes them all the more cumbersome. this is just another reason the modern touhou games are more pleasant plays at least imo.)