Vorticon HyperPistol
The Vorticon HyperPistol is the weapon used by Keen in Episode 2 of the Commander Keen series. Keen finds a nearly empty HyperPistol at the start of Keen 2 just after sneaking onto the Vorticon Mothership. He finds further pistols during the game and adds their ammo to his own (each pistol carries five charges). Keen is believed to only carry one pistol throughout the game, but this is unproven.
The HyperPistol is the same weapon used by the Vorticon Elite on the Mothership, though the elite appear to have an unlimited supply of ammunition with them. They also seem to shoot different blasts (red), a fact possibly explained in Keen Dreams where Keen mentions several settings on his HyperPistol including "Stun", "Disrupt" and "Fry to Delicate Brown". (By Keen Dreams, Keen has only two shots left in his HyperPistol.)
The HyperPistol is an energy weapon, like most of those in Keen, and shoots blue energy bolts. Contrary to persistent belief, the HyperPistol kills enemies rather than stunning them, a fact mentioned at the end of Keen 3. The HyperPistol replaces the Raygun Keen acquires in Keen 1, and is in turn replaced by the similar Pistol in Keen 3, and by another weapon (possibly of Keen's own design), the Neural Stunner, in episodes 4–6.