Bullets are fast projectiles that go in a straight line. These are the only enemy projectiles which terrorists can't hurt themselves with, unless being stunned or their bullets are being deflected back at them.
Missiles have either homing capabilities, fly in a wavy pattern or are combinations of both. Missiles can be shot down with bullets and other projectiles.
Grenades can be thrown back with a melee button.
Enemies have different reactions:
- This reaction is signified by an exclamation point above the enemy's head. Some of the enemies will put their gun in a firing stance. Aliens tend to move faster in alert state. Alert state is caused by the following:
- Spotting an enemy.
- Being in the hearing radius of Alarm.
- Being alerted by Scout Mook.
- Dogs and hellhounds also become alerted just from hearing noises.
- This reaction is signified by a screaming sound and the enemy running away from the source of Fear. Enemies react with Fear toward the following:
- All grenades when they're about to blow.
- MacBrover's basic dynamite (when not giving distracted reaction)
- All types of fire, including B.A.'s flamethrower, Snake Broskin's molotovs and any fire caused by explosions.
- Bees from a bee hive.
- Proximity of Bro Dredd's missile.
- Seeing a result of Brochete's Brodator's and Ash Brolliams' melee attack.
- Broheart's and Ash Brolliams' special.
- Getting hit with Indiana Brones' whip.
- Player under the influence of vitamins.
Terrorists can also get fear status for:
- Being near various aliens.
Mechanical enemies are immune to fear.
- This reaction is signified by spots around the enemy's head and has a duration of 8 seconds. Enemy may stand still for several seconds, or move around aimlessly. When moving around, the enemy may attack with a weapon in confusion if having one. When that weapon shoots regular bullets, they don't hurt Bros but damage mooks and various other enemies. Enemies with explosive weaponry can still damage the bros. Suicide-based enemies will go into suicide mode. Enemies react with Confusion to the following:
- Bro Hard's flash grenades.
- Bro in Black's neuralyzer.
- Stun, like confusion status, is signified by spots around the enemy's head. Stun usually lasts a short time. Stunned enemies stop firing momentarily and some stuns make them stop attacking altogether. Stun is caused by the following:
- Bronan the Brobarian's small shockwave.
- Ellen Ripbro's primary fire.
- Brolander's and Broden's lightning when it doesn't explode the them.
- Mr. Anderbro's dash.
For facehuggers, shooting its egg off the ceiling or wall causes the emerged facehugger to be stunned for a short time.
- This reaction is marked by ? over their heads. Most enemies with distraction will stop attacking. Dogs, hellhounds and aliens become active and may move towards the player. Distraction is caused by the following:
- Noises such as door opening/shutting, explosions and firing weapons. Noises also make enemies turn towards the source of the noise.
- Sometimes when MacBrover's TNT is attached to them.
- Activating Double Bro Seven's disguise or Brodator's special.
- This reaction is signified by a question mark above the enemy's head. This causes most enemies to move toward the source of Curiosity. Mooks react with Curiosity toward MacBrover's Turkey Bomb, and Brodator's corpse. Aliens also react with curiosity to alien pheronomes.
Flying suicidal enemies fall down and explode when gaining curiosity status.