Forge World
Zealot
Countdown
Battle Canyon
Penance
Solitary
High Noon

Pistol
    The first changed weapon is the one you spawn with. The Pistol has received a great damage buff, able to kill a player in only 3 headshots as opposed to default Reach's 5. The magazine size has also been increased to 12 to match Halo CE. To balance out this power, the projectile has been slowed significantly so that leading your shots at longer range will be necessary. Bullet spread has been entirely removed so that the player will be entirely responsible for where their shots travel.
    
Assault Rifle
    Your trusty sidearm, the perfect tool for cleaning up a weakened opponent when you are low on Pistol ammo. The Assault Rifle fires much more quickly than its default counterpart, and its accuracy is much more controllable. It now sports a 40-round magazine to fire for even longer. This weapon's aim assist has been reduced drastically in order to make up for its more consistent performance.
    
Fragmentation Grenades
    Frag grenades, mechanically, return to how they were in Halo CE. The grenade's fuse timer will not begin until it comes to rest, forcing a player to place each one properly and predict their opponent. In an attempt to make these grenades perform more consistently, bouncing has been normalized across all surfaces. No longer will sand, grass, or Covenant ships cause grenades to become stuck.
    Frag and Plasma Grenades can no longer be shot out of a player's hands, nor can ones on the ground be manually detonated with gunfire.
    
DMR
    The DMR has seen fewer changes compared to the previous weapons for familiarity, but still finds a purpose in this sandbox. Its magazine has been reduced to only 12 shots, but damage has been increased to kill in 4 headshots, one less than previously. The damage has been tuned specifically so 2 shots from a DMR will leave a player vulnerable to a single Pistol headshot. This makes the weapon great at long-range support, as its bullets retain their instantaneous travel time.
    
Shotgun
    As with the DMR, this weapon has also received a relatively small amount of changes. The range of its pellets has increased in order to make the weapon function more reliably alongside the higher lethality of GPMA's sandbox.
    
Rocket Launcher
    The weapon to have received the least amount of modification, the Rocket Launcher now has no aim assist. Rockets will always go where you point them, and enemy players will be unable to move your reticle in unexpected ways.
    
Sniper Rifle
    Made to be much more punishing to those who are not accurate with their shots, the Sniper's aim assist has been reduced significantly. As a balancing measure, the rate of fire has been greatly increased to allow it to still squeeze out a kill against enemy Pistol users by just hitting body shots.
    
Grenade Launcher
    Similar to Frag Grenades, the Grenade Launcher's projectiles will always leave a player with low shields if one is caught within the blast radius. The weapon will still one-shot a player with a direct hit as normal. The secondary hold fire has had its blast radius reduced, encouraging players to try and be accurate with the less forgiving primary fire.
    
Plasma Pistol
    The primary arm of the Covenant's Grunts. The primary fire of this weapon has remained largely unchanged, while its charged shot has received a large amount of changes. The weapon will now charge up approximately twice as quick, and no longer drain battery while holding its shot. The charged shot itself now has a small shockwave that can be used by clever players in order to jump to heights they normally would not be able to.
    
Spiker
    Commonly seen in Brute hands, the Spiker in GPMA has been modified to function similarly to CE's Plasma Rifle. Players hit by sustained fire from this weapon will have both their movement and aiming slowed. While its individual shots may be weak, it may leave an ambushed target helpless. As this weapon's barrels heat up, it will fire even faster. The Spiker also has a uniquely increased melee range, allowing it to reach out further than any other weapon in the game.
    
Concussion Rifle
    No longer a magazine-fed weapon, the Concussion Rifle will now fire 10 shots in a row before depleting its battery. The impact damage of its shots has been increased to kill in only 2 shots, rewarding accuracy the most out of every explosive weapon in the mod. Splash damage has remained unchanged to reward accuracy even more. The Concussion Rifle's projectiles now have even more knockback, allowing players to perform jumps with it similarly to the Plasma Pistol.

Focus Rifle
    Every aspect of this weapon has been made more extreme. Similar to Quake's Lightning Gun, this weapon now deals extreme amounts of damage in a small amount of time. This increased power comes at the cost of higher heat generation and battery consumption, players will not be able to keep this weapon around for nearly as long as they could in the base game. The weapon's range has also been reduced, forcing its users to get closer in order to deal damage with this weapon. The Focus Rifle's scope magnification has been adjusted to suit this shortened range.

Brute Focus Rifle
    "A prototype version of the Focus Rifle. Not yet capable of sustained fire, this primitive Focus Rifle design opts for building up a charge over time and expelling it all at once."
    The Brute Focus Rifle shares many of its mechanics with Halo 4's Railgun. Players charge it up for a short amount of time, and then fire a single shot that will instantly kill a player regardless of where it hits. Like the Focus Rifle, this weapon is still powered by a battery. The lack of reloading means a player can switch away in the event of a missed shot, and not be rendered helpless.

Needler
    Finally, we have the Needler. This weapon has been entirely overhauled from its original state. No longer is it a fully automatic weapon that fires homing projectiles. Now, the weapon is similar in function to Quake Champions' Tribolt weapon. Needles now have a small explosion radius and will lodge themselves into any sort of material before detonating. Firing in bursts of 3, a player with good aim will be able to instantly kill an opponent with a supercombine. While they will not kill instantly, Needles lodged into the environment still pose a threat and can deal a large amount of damage in groups.

Player move speed, acceleration, and air control have all been increased to speed up the game's overall pace.

Active Camoflauge was extended to a 45 second duration, with camouflaged players being more difficult to see compared to the base Halo Reach
Overshield provides two extra layers of shields and has had its charge time increased dramatically. The effect of this is that players do not need to remain invulnerable for as long as default Halo Reach, while gaining even more of a benefit.
Custom Powerup acts as a weaker Overshield, providing only 1 extra layer of shields.
Players will have their armor changed to a gold color to denote invincibility after picking up the Overshield or Custom Powerup.

Players will now drop their Armor Ability upon death.

Melee Lunge has been entirely removed. The range of melee attacks has been increased to compensate. Players are now expected to more accurately aim their punches.

Team colors have been adjusted somewhat to contrast more with certain maps.

Reticles have been adjusted to be smaller, as have viewmodel positions been shifted. It is recommended to play this mod with Centered Crosshairs enabled.

Flinch has been removed on all weapons. A player's reticle will no longer move while taking damage.

Autoaim and Magnetism has been reduces on all weapons in order to balance out controllers and keyboard players better than the base game.

Lights on all Forge pieces have been removed in an attempt to increase performance.