This is the definitive Gradius game by a wide margin. It's unbelievably good. Even better with two players. I honestly think this is the best shmup to come out in years.
People know how much I like games with a big arsenal so I'm sure you all know why I like this so much.
It's a total fan orgasm to play too, in second level you fight like half the bosses from Gradius II and Life Force, the Vic Viper pilot in the cutscenes is voiced by the guy that's done all the voices in Gradius II and up, wonderful stuff. Even has a horrendously easy final boss as all Konami shmups absolutely must.
One caveat, it's a CD game, blue disk. Gradius deserves better.
Either way the game in and of itself is art. Everyone knows I like to go into huge rants about games I like, I can't with this one because it's that hard to describe how fantastic it is.
Brilliantly, there's even a boss where DOUBLE is useful!