There are many unique weapons to be found within the game. This guide will tell you about the weapons, their advantages and flaws.
Knife- This is the most basic weapon in the game. It can be used for stealth kills on unknowing enemies, or to attack an enemy head-on while he is reloading or getting up from a grenade blast. It can also be used to take down a dinosaur in one move-you can take on a whole pack of dinos with your Knife! However, this will not work on all dinos. Don't expect this to be your all-purpose weapon though, if you get up close to an enemy and push the attack button too soon, the enemy will be able to attack you. And the secondary attack is just a horizontal slash, that does little damage.
Bow- The Bow allows you to take out an enemy from a distance without being seen or heard. The more tension you put on the string, the harder the arrow will hit, allowing you to take out more heavily armored M-G Soldiers. You can also add an explosive effect to your shots by picking up Tek Arrows. The Bow is not recommended for use against dinosaurs however, most are too fast for you to accurately aim and fire. And don't forget, you have to compensate for the arc of the arrow for more distant targets, so be sure to aim high!
Pistol- The Pistol is a well balanced weapon that is accurate enough to take out enemies at medium range, but powerful enough to take out a dino with a few well-placed shots. It's Alt. Fire is a quick burst that allows you to do more damage to an enemy. If you duel-wield another pistol, you can take down most enemies pretty quickly. Don't try to hit anything from long range, especially with burst-fire, the recoil will blow you off-target, leaving you open for attack.
SMG- The SMG is one of the better weapons in the game. It has good accuracy at medium to long range, and can be equipped with a silencer for quiet kills(just make sure you aim for the head!). It too can be duel wielded to give you some extra firepower. But it is not so effective against fast-moving dinos, or heavily armored M-G Soldiers
Shotgun- The Shotgun is an excellent dino-killer, but is not so effective against M-G Soldiers. The secondary flare launcher can be used to move dinos away from you, or to make them attack each other, giving you time to reload and take them out.
Chaingun- The Chaingun is a beast when it comes to laying down a field of fire on your enemies, but its slow reload make this a risky weapon to use. The Chaingun also needs time to wind up before it starts firing, this can be avoided, however, by pressing the Aim Button to keep the barrel rotating. The secondary fire allows you to place the Chaingun on the ground to act as a stationary turret, but it can be knocked over by enemy attacks, or if it runs out of ammo.
RPG- The RPG is a brutal weapon. It's explosive power will take out almost any M-G Soldier or dinosaur in one hit! The rocket detonates about a second after making contact with an enemy or hard surface, and the splash damage will take out anyone else nearby-even you! The secondary fire allows you to lock onto your target before firing, allowing you to just fire-and-forget.
Pulse Rifle- The Pulse Rifle fires low energy uranium slugs at a high rate, allowing you to take out most Soldiers quickly. The biggest drawback of this weapon is that if you get trigger happy, the gun overheats, and takes several seconds to cool down. The secondary fire launches Disruption Grenades that blow an enemy out from behind cover, giving you a free shot.
Sniper Rifle- The Sniper Rifle is a great long-range weapon, but is absolutely awful in a close-range gunfight. The rounds are powerful enough to take out any enemy in one hit if you place it right, and the secondary fire allows you to look through the scope for presise shots.
Blackfly- The Blackfly acts as a sticky-bomb launcher, allowing you to place a bomb on a target, and detonate it when you choose to. It's great for taking out groups of dinos, or for taking out armored M-G Soldiers, but isn't good for big firefights. The secondary fire lays down a group of Proximity Mines, good for covering places where enemies may try to flank you.
Flamethrower- The Flamethrower is a good and bad weapon. Good for being able to take down a dino or bug fast, bad for not being able to take on more than 3 enemies at a time, and for only being able to use it a close-range. It's also practically useless against M-G Soldiers, they almost always take you out before you get close enough to fire. The secondary fire launches a Napalm Grenade, good for taking out groups of enemies.