Items appear in item boxes, as well as from enemies defeated in close combat. The main items are as follow. There are also hidden items, so keep a lookout for them.
Heavy Machine Gun
Rapid-fire machine gun. Capacity: 200
Vulcan
Top-tier heavy machine gun. Capacity: 200
Flame Thrower
Burn enemies with powerful flames: Capacity: 200
3-Way
Gun that shoots in 3 directions. Capacity: 100
Tank Buster
A powerful weapon to use against tanks. Capacity: 30