Tied for my favorite Touhou game with 12. Like that game, this has some of the best spellcards, music, characters, and general atmosphere and flavor.

It's one of the simplest games in the series, but I like how punishing it is. Power and bombs are one resource like in 10, but you can only get life pieces from clearing or bombing spellcards - you won't get one if you die. Scoring is simple too, mainly based off grazing which returns after being absent in 10 for some reason. It's all pretty basic, but the extremely strong bullet pattern design makes up for it and that's ultimately why I think of 11 so highly. Just a really well-executed, well-designed game

I have no love for this game. Power-based bombs ruined what I think could have been a good game becuase now any small defeat you take in having to bomb a spell card inherently makes you weaker, causing a terrible spiral from even just the act of bombing, which originally was your chance to save yourself before spiraling. Beyond some of the patterns in this game being particularly RNG based, I also find some of the patterns in this game to just be fucking boring or frustrating, namely patterns where you can't shoot the boss or the boss will move all over the place, like with Suika-Satori or Parsee.
This game's soundtrack is excellent, and it has some great patterns in there, but then is held back by ZUN vastly overcorrecting in the wrong way on a broken system that was the result of him trying to fix what was not broken in the first place, breaking the already broken system even more. Even so, for how much I grew to despise this game, the cast is still great, and establishes Suika as a character who is much, much more important than we would have thought beforehand.
Favorite track - Solar Sect of Mystic Wisdom ~ Nuclear Fusion (Stage 6 boss theme)