What weapons are on the left 4 dead 2 demo

That's a hard one. I'll list the ones I can think of.

Melee:
Guitar
Machette
Night Stick
Frying Pan

Weapons:
Magnum Pistol
Dual Pistols
Two Auto Shotgun
Two Pump Shotguns
AK-47
M4
Some kind of assualt rifle

Also on Melee
Samurai Sword
Chainsaw
Baseball Bat (if you preordered it or bought the code for it)