wait there are actually people which enjoy StB?
There are 4 stage themes, 5 if you count Wind God Girl for 10-8. The speed and gameplay are just something to get used to. There are many different interesting spellcards in the game, several of which ZUN considered good enough to reuse for Satori, and others which require clever use of you bullet removing camera or acknowledgement of how a pattern works to beat them. Because of that, it has a larger puzzle element than the rest of the games, but that isn't really different from the extra bosses where usually half the spellcards require or are made very easy by the use of a trick.
So yeah, it is different, but it is still a fun game.

Hmm, maybe I should give it a try again, I still haven't cleared all scenes. I stopped when I finally beat Kaguya's infamous Ceiling attack... took only ~ 900 tries...
Ok, I think I can see why many people don't like the game. :V But it is not a bad game, nontheless.
On Topic: Yes, I think I really
do have lost all my selfmade danmakufu scripts.
Definitely worth a red UFO invasion.