Commander Keen can use this weapon to stun his enemies temporarily. The Neural Ray Blaster does have unlimited ammo, but unfortunately will only shoot one blast until that blast hits something or goes off the screen.
Found in: Keen GBC
Neural Stunner Item
Commander Keen's weapon of choice in Keen 4-6. The gun fires a green blast of energy, stunning anything that happens to get in the way. You have a limited amount of shots so be sure to collect them if you happen to find one in a level. They are worth 5 ammo.
Found in: Keen 4, Keen 5, Keen 6
Neutrino Burst Injector Location
A level in Keen 5 with one of the four machines you must destroy to activate the teleport.
Found in: Keen 5
New Vorticon Location
A city on Vorticon VI where life is a dark, dangerous enterprise. It's a level in Keen 3.