Revolver: purely tutorial and early game gun/ does Decent damage with Good accuracy and a Medium/Slow fire rate
Shotgun: stereotypical shotgun Close Range High damage Decent fire rate easy to hit things with spread but also easy to miss / early game gun.
Burst Rifle: THE ONLY REASON TO USE THIS IS FOR THE HARBINGER do not use it anywhere else you will just take damage due to misses / high damage weapon for Harbinger Fight
Sniper: High damage High range Great accuracy / good to get easy kills on some enemies early wave and hitting enemies out of the air / Also AWESOME PIERCE ON THIS GUN use it for groups when you are on the ground
Crossbows: The crowd control weapons Low damage Okay accuracy Fast firerate TONS OF AOE / Use with double jump or jump pads to get above the enemies and do a TON of group damage
Sword: Its a sword that one shots enemies... / don't buy it unless you want the achievement for buying all weapons
LMG: It is the middle line of all of the weapons Okay accuracy Okay damage Fast firerate Okay range / This is the weapon i have used the least but you could use it almost everywhere on the ground

Yours Truly
-Squibbles