A review I found said that for the earlier Psikyo games, the individual releases aren't any different from the ones in the compilation.

Right now I'm not sure where my tastes in shmups lies.... except that I really, really wish the Darius collections would go on sale, because I always wanted a thing called tuna sashimi.

Also I'm not giving up hope on Super Contra. I mean it also took them four years to do Super Punch-Out (the arcade one, not the SNES one).