#10: Cerebral Bore. My opinion: Not perfect, but fun to watch.
#9: Chainsaw. My opinion: Good, but got boring after awhile.
#8: Spread Gun. My opinion: Not really that good of a weapon.
#7: Railgun. My opinion: Good...when you're desperate for anything that can kill.
#6: Laptop Gun. My opinion: Your average machine gun. Slightly better with the wall-turret thing. But not perfect.
#5: Energy Sword. My opinion: Cheap, but fun and easy as hell to use.
#4: Ice Beam. My opinion: Pretty good and interesting to try out.
#3: BFG (Big Fucking Gun). My opinion: A glorified rocket launcher/heat-seeking-missle/laser gun. And I love it.
#2: Red Turtle Shell. My opinion: You get an almost orgasmic feeling when you get this. Fun as hell to use.
#1: Gravity Gun. My opinion: With the valve physics engine and this gun, your dreams of crushing zombies with cars can come true. BEST. GUN. EVER.