This is fun but it gets a little repetitive. The zombies are only so intelligent, they can't get to me when I'm on top of the church or something. The closest thing to a sniper is the revolver, so I kinda wish there was a long barreled rifle, but I guess that would defeat the purpose of leveling.
On the other hand, leveling could upgrade the guns?
Level 1 sniper: nothing
Level 2 sniper: iron sights
Level 3 sniper: ACOG scope
Level 4 sniper: silencer
Level 5 sniper: new bolt for faster rotation/more power to the bullet AKA higher ROF / DMG
Level 6 sniper: zoomed scope
Just a thought, that might be hard, I wouldn't know. But it's kinda similar to bushido's sentries in a way... Idk.