I've been asked about the guns and the leveling system of GunGirl2. Instead of leveling your character over the entire game, which for me makes sense for true RPG kinda games but not for action oriented zombie shooter platform kinda games, I've decided to do something else.
There are 6 different kind of guns you can hold at a time (maybe I'll give you the option to trade a weapon for a new one later in the game, but back to the point now). Each gun has it's own type of ammunition and a weapon level. This level increases each time you pick up a certain amount of 'G's (which stand for... gun... level.... thingy.... no wait, gun power!). Those things are dropped by enemies. The harder the enemy, the more G you get (kinda like experience points).
But if you get hit by an enemy, your current weapon will lose a bit of it's G power and maybe drop a level. This is to make sure you don't just level up one weapon and only run around with this one until your ammo runs out.
For example if you run around blasting things with your shotgun and the zombie dudes drop a lot of Gs, you will level up pretty quick. But if you encounter a hard enemy and he hits you a couple of times, your shotgun will power down and you might want to change to a weapon that is still at max level to deal more damage on that enemy. This difficult enemy will possibly drop a lot of G after defeat so you can switch back to shotgun and level it up again.
If you only level one weapon and this gets powered down by strong enemies, you will have a much harder time against them.