Not sure if this was already brought up, but
Conagusuri (a music doujin circle) and with the help of Peposoft made a Touhou Mega Man/Rockman game called
Touhou Koukayaku: The Game (東方虹華薬 The Game) that's kinda like Twilight Frontier's Mega Mari, except this game was based on
Unidentified Fantasic Object. You get to play as Byakuren Hijiri, and later, Ichirin, Minamitsu, Shou, and Nazrin by swapping them out in the way you'd switch weapons in a Mega Man/Rockman game, and each character has their own unique shot-type. The game was actually released at C79 with Touhou arrangement they've released (
official site/Japanese).
[youtube]http://www.youtube.com/watch?v=vvFafZ04wBA[/youtube]