(I guess it would've come sooner or later)
Warning forever is a 2D fixed shooter game which very closely resembles Fraxy.
In this game you fight a line of different bosses until you finally get to the last one and defeat it.
It's a pretty simple game with a pretty simple shooter style which probably makes it so much fun to play.
(http://img16.imageshack.us/img16/3241/39540862.png)Taken from wikipedia :P
And you can download it here: http://www18.big.or.jp/~hikoza/Prod/