Pistol
This really isnt so great, but it doesnt have bad recoil. If its all you got, aim for the head.
Revolver
It does high damage, but it shoots slower and isnt great at dealing with hordes. Its still better than the pistol.
Laser Gun
NOTE: THIS GUN IS ONLY IN PART 3.
This is easily the best pistol. it one shots every zombie. Use it wisely though as ammo will not be on your side.

M16
Fast firerate, but not great damage. If you aim for the head that damage wont matter. Great at dealing with hordes but should be used after the AK-47 is out of ammo.
AK-47
This gun shoots slower than the M16, but makes up for it with its great damage. This thing is unstoppable with lots of ammo and headshots. If you use this often, you will probably run out of ammo quickly. Be wise with its ammo. It is also good for picking off enemies from far away.
Thompson(or Tommy Gun)
Only in Part 2, and Part 3.
This is better than the AK-47, it shoots at the rate of the M16 with the AK-47's damage. This mows down enemies but has a 30 round magazine, compared to the AK-47 and M16's 50 rounds.
Lots of ammo is supplied though.
Uzi
Not much to say. Great in Part 1, but garbage in all the other parts. It has 50 rounds, but that is not enough for the firerate. 5 mags can be wasted in under 45 seconds. It has so little damage that it can barely even kill A NORMAL ZOMBIE WITH 1 MAG. And bandits and armed zombies? 3 MAGS! 3! Dont use this after part 1, its only even good in the church level.

Shotgun
The greatness of this gun depends on the range. Close enough can be a one shot, far away enough could be 1 and a half mags. Its an ok weapon and extremely good in close range combat, but thats it.
Auto Shotgun
ONLY IN: PART 2 AND PART 3
This. Is. GREAT. But be wise with your ammo. Thats all i really have to say about this gun.

Minigun
Good Damage, and just the right firerate to save ammo. Its a great choice but it can only hold two mags, if you run out of ammo, go back and grab more.
Grenade Launcher
Not that good against hordes of pigs or armed enemies, but great against normal zombies. Its a meh weapon.