I figure I might as well share another doujin game that I enjoyed. This time it's a shoot-em-up I played right when it came out and really loved it. As the title states, it's a shoot-em-up in which each stage represents a "generation" in the history of shoot-em-up games. You start off in a space-invaders-esque level and "evolve" through collecting little gems. A neat feature is depending on your playstyle, you can evolve in different ways, although not in any really wacky way, but there's still enough variation to allow some extra fun in altering your playstyle for different powers.
Video:
It's got pretty decent music too.
Game:
http://www.tatsuya-koyama.com/software/wg002_genetos_eng.htm...