Cut Halo: Combat Evolved weapons
From Halopedia, the Halo wiki
During the development of Halo: Combat Evolved, the game went through many different styles including a strategy game, a third-person shooter and a first-person shooter. Throughout these iterations, many different weapons were cut from the game, some of which presenting notably different design styles from those found in the final 2001 release. Most known cut weapons are from the 1999-2000 era builds of Combat Evolved, during which time the game was intended to be a third-person shooter. However, a small handful from the FPS era are known.
At the time of the game's development, Bungie had a creative attitude to weapons creation - weapons were often designed with a question of what could be done, with details of how it might work in-game left to be figured out later. Due to this, there is no guarantee most of these weapons would have ever made it into a final build. However, the ideas or designs for many of them would later make their way into subsequent Halo entries, in particular Halo 2.
Anti-air rocket launcher
Referred to in-game as the SPNKR 108 8AM, this weapon was described as being a rocket launcher intended for use against aircraft, while the standard rocket launcher was intended for anti-vehicle usage. A similar design was later concepted for Halo 3 as the G4H-DuSH, though was similarly cut. The M57 Pilum would later debut in Halo 5: Guardians, bearing some broad similarities to this rocket launcher.
The chaingun is a tri-barrelled rotary cannon that could be held with two hands by the player. It was frequently seen in promotional material for the game including the first-ever screenshot released, though was ultimately cut. The concept was later revived with the AIE-486H machine gun in Halo 3.
Bolt-action sniper rifle
Referred to in-game as the SWS99C-S2 and jokingly by developers as the "old shovel", this weapon was to be a bolt-action rifle featured in Halo.
Labelled in-game as the Pattern-2 Composite Sword, the machete was to be a human counterpard to the Covenant energy sword. Early revisions of John-117's armour had a port for the Machete to slot into. Althought the weapon was modelled and animated, it was never made functional as a weapon in-game. Although the machete was cut, it did live on in-game and in-lore as the Machete - a UNSC bladed weapon for use in jungle environments and found on all variations of the difficulty sigils for Normal, Heroic and Legendary difficulties.
Labelled in-game as the Lamprey Sub-Ed, the spear gun was intended for underwater combat against sea creatures. When fired, its projectiles would stick into enemies akin to those of the Needler and Spiker in later games.
While not strictly a weapon, Sangheili wielding arm-mounted shield-generating gauntlets akin to those employed by Jackal infantry can be observed in concept art and screenshots. A similar device lives on in Halo canon.
The gravity rifle can be found in the files for released builds of Combat Evolved, though lacks textures, first-person models, animations, stats or projectiles. The weapon can be enabled on some maps in Halo Custom Edition by using the command
Appearing to function akin to a grenade launcher, the gravity wrench features two prongs which charge up and generate an energy ball between them, which is then launched on a projectile arc.
The weapon labelled
Particle beam rifle
Found in the 2000-era builds and labelled
This weapon appears in a handful of promotional screenshots. Almost nothing is known about it. The presence of fairly final-looking Forerunner architecture and Elite model suggest it was present in the later-era FPS builds of the game.