It's one of my favorite shooters. $25 is a great deal. It takes *lots* of practice to get really good at it. Much of the game is about memorization, as score is everything. There are very specific patterns to destroying enemies. It's very difficult in this sense, but is not impossible.
It's a different kind of shooter, but is probably one of the best I've ever played. Great play machanics, awesome graphics, superb music. Typical of Treasure.
I know it's blasphemy, but I find it to be much better than the majority of PCE shooters... And that's saying a lot. I think that it's just because it's so unique.