Random Nico Nico Douga: IOSYS

Three popular videos on Nico Nico Douga are 魔理沙は大変なものを盗んでいきました, チルノのパーフェクトさんすう教室 and 患部で止まってすぐ溶ける ～ 狂気の優曇華院, totalling over six million views. All three are Flash animations to promote remixed soundtracks by IOSYS from various bullet shooters by Touhou project, which makes bullet curtain-style shooters.

What's a bullet curtain-style shooter, you might ask? They're shooting games similar to Defender, Gradius and R-Type, except the scrolling is vertical, there is no landscape to crash in and copious amounts of bullets appear at the same time, with having over a hundred brightly colored insta-death objects to track on screen being common.

Also, oddly enough, a friend told me that there is a karaoke place in Montreal with 魔理沙は大変なものを盗んでいきました on the track list. I'll write more about it once I get more details about the place.