The following weapons are available

Pistol
Starting weapon, clip holds six rounds, does x1 damage, recommended for easy runs.

Shotgun
Unlocked after five Supply Depot trips, clip holds two rounds, does x2 damage, recommended for easy and medium runs as well as easy and medium Bosses.

Sub machine gun
Unlocked after twenty runs, clip holds six rounds, does 2x damage, recommended for easy, medium and hard runs and easy and medium Bosses.

Rifle
Unlocked after thirty runs, clip holds single round, recommended for easy and medium runs as well as easy and medium Bosses.

Assault rifle
Unlocks after sixty runs, clip holds five rounds, recommended for easy, medium and hard runs, and any Boss difficulty.

Chainsaw
Unlocks after eighty runs, recommended for easy, medium, and hard runs, and easy and medium Bosses.

Minigun
Unlocks after one hundred and eighty runs, unlimited rounds, high damage, recommended for any mission or Boss.

Grenade launcher
Costs 120 dollars.