Loved the gameplay, the music, the graphics/art style. Heck, even the plot was good (anime-ish WW2, hey not bad).
I still haven't finished it, some of the level designs are just awful and the enemy AI is kinda dross. There seems to be lots of great stages in the game and a handful of really shitty ones and I keep getting stuck on those and only coming back to the game about eight months later.
Still, I like it a lot, I'd say its an almost great game that's weighed down by some occasional flaws.