My experince in shooters is mostly limited to the DC, Genesis, and SNES so here's some DC information based on my 3 game library.
You NEED Mars Matrix is you have any interest in shooters whatsoever. It can be had for $15-$20 with ease, and offers countless hours of beatiful vertical shooter gameplay.
Gigawing- everytime I play this game I get a "meh" fealing. It's not terrible by any means, but it isn't something I really enjoy playing.
Gunbird 2- Awesome.......the challenge is insanely high (That's not a bad thing, that's a good thing), the storyline contains sexual inneundos out the wazoo, and the gameplay is typical Psikyo goodness. Add in the extremely low price and you've got yourself a bonafide winner.
