Selvokaz said: does no one else find it strange that Aigis will be shooting people? What is she using rubber bullets?
Naoto uses a gun too. Besides, check out the crazy stuff other fighting games have characters use on each other(looks at Soul calibur). Bushido Blade is the only fighting game I've ever seen that was actually realistic. As in you could win fights with just 1 well place sword swipe. Heck I've won some matches by throwing my sword straight into the enemy.
Plenty of fighting games have guns, especially 2D ones, and they are usually not any deadlier than the swords or even bare hands that the other fighters have. Heck, in some cases they deal even less damage than a normal punch, or are only used in special attacks. So I wouldn't worry too much.
And besides this is going to be an armed fighter like Guilty Gear, Blazblue, SoulCalibur etc, so everybody will be stabbing, chopping and crushing their best friends without dealing any permanent damage. That's part of the genre.