If you frequent the chatbox whenever I'm around, you know that I play this obscure series of games. Touhou is a series of shoot-em-ups, produced by Team Shanghai Alice, which is actually comprised of one man, who goes under the pseudonym of ZUN. In most of the games, you play as either Reimu Hakurei, a shrine Maiden, or Marisa Kirisame, a witch in an attempt to solve a bizarre, supernatural incident.
There are 5 games for the (now obselete) PC-98, so the windows series starts at 6. Most of the series are shmups, however, there are 3 spin-off fighters too.
If you want a link to where you can download the games, then PM me. I don't bite~. If you're a big shmup fan then do try them out, as they are a lot of fun. Also frustration, since they can be very difficult in the latter halves of the games!
You may wish to visit the Touhou Wiki for backstory, plots and character backgrounds.
^That video shows a playthrough of one of the stages, specifically, Touhou 10: Mountain of Faith stage 4, normal difficulty.