― Doom instruction manual
The Plasma Gun (also known as the Plasma Rifle in the game manuals and help screen) is a futuristic weapon with a barrel that roughly resembles an accordion, which fires blue and white bursts of plasma. It shares the player's stock of cells with the BFG9000 as a source of ammo.
- In the Doom press release beta, the plasma gun fires green-white and orange-red bursts, alternating between the two colors. This is similar to that version's BFG9000, which fires 40 of the same projectiles per shot. For the release of Doom, these plasma bursts were made blue-white, and the gun sprite was changed slightly.
- Like the shotgun, the plasma gun was created from an existing toy gun.     The links show a dart-shooting, M60-like toy that was popular in the early 1990s (back then, it was tan). The area in front of the bipod could be detached to use as a separate weapon. The designers simply turned the detachment around so that it was shown backwards. The resemblance is most apparent when the player lifts the weapon at the end of a volley.
- The rapid fire of the plasma gun often requires many sprites to be rendered simultaneously. This has been known to cause lag during multiplayer games or on older machines (see also the notes on the early BFG).
- The Plasma gun will sometimes gib zombiemen and shotgun guys due to their rather low health (20 and 30 hit points respectively, while each plasma burst can do as much as 40).
Appearances in other id Software games
- The Doom 64 plasma gun sprites are completely redrawn. It has a blue electric tube on top, which makes a constant buzzing sound. Like the shotguns, the recoiling animation is non-existent, likely to save cartridge space. Other than that, the "new" Plasma gun fires at a slightly slower rate.
- The plasma gun appears as a redesigned version in Quake III Arena, another game later developed by id Software. The Quake III plasma gun has a more streamlined, futuristic look with glowing plasma visible behind transparent parts. The plasma projectiles travel at a higher velocity and create a small radius of splash damage upon impact.