Rocket Launcher

The Rocket Launcher (or RL, as it's known) is a weapon that has appeared in various incarnations in all of the Unreal series.

Unreal
The Rocket Launcher in Unreal is called the Eightball Launcher. This is due to the ammo it uses, Eightball rockets, and is based on the eight ball in pool. Can load up to six Eightball rockets and fire them in a straight line or a spiral configuration by holding down the alternate fire button while the rockets are being loaded. Can load up to six Eightball rockets as grenades. The rockets will bounce around before they detonate. The maximum amount of Eightball rockets the Eightball Launcher can hold is 48.
 * Primary Fire
 * Secondary Fire
 * Ammo
 * Damage

Unreal: RTNP
Unreal - Return to Na Pali has the same Eightball Launcher as Unreal does but it also adds a standard Marine Rocket Launcher to your arsenal.

Unguided rocket projectile. Guided by moving/aiming crosshairs.
 * Primary
 * Secondary

Unreal 2
A.K.A. Shark.

Unguided rocket projectile.
 * Primary

Rocket breaks into four smaller projectiles that fly around drunkenly when secondary fire button is released. Holding down the secondary fire button and moving the crosshairs over enemies before release will lock each rocket to a target, one at a time.
 * Secondary

Unreal Tournament
Fires up to 6 rockets at a time, released in a horizontal line formation or, by pressing alternate fire while loading, in a tight cluster. Fires up to 6 grenades at a time. Grenades bounce from obstacles and explode after a certain amount of time or on contact with player. Upon pick up Rocket Launcher will contain 6 rockets, maximum ammo capacity being 48. Default ammo pack has 12 rockets in it. Direct hit by rocket or grenade delivers 112 damage to a target.
 * Primary Fire
 * Secondary Fire
 * Ammo
 * Damage

Unreal Tournament 2003
Fires a single rocket. Fires three rockets in a horizontal line, and, by pressing primary fire while loading, can shoot up to three rockets in a tight spiral. Rocket Launchers have 12 rockets when they are picked up, and they can hold a maximum of 30. Rocket Launcher Ammo Packs hold 9 rockets each. It takes a bit under 1 second to load a rocket.
 * Primary Fire
 * Secondary Fire
 * Ammo
 * Damage

Unreal Tournament 2004
''The Trident Tri-barrel Rocket Launcher is extremely popular among competitors who enjoy more bang for their buck. The rotating rear-loading barrel design allows for both single- and multi-warhead launches, letting you place up to three dumbfire rockets on target. The warheads are designed to deliver maximum concussive force to the target and surrounding area upon detonation.''

The Rocket Launcher in UT2004 is identical to the one in UT2003.

Unreal Tournament 3
The UT3 Rocket Launcher is reportedly about the same as that of UT2003/4, possibly without the capability to shoot only two rockets in a spiral.

Unreal Championship

 * Primary Fire
 * Secondary Fire
 * Ammo
 * Damage

Unreal Championship 2
Fires a single rocket. Charges up to three rockets, each of which can split in two if activated in midair.
 * Primary Fire
 * Secondary Fire
 * Ammo
 * Damage

Tactical Use
The Rocket Launcher's rockets fly straight, do a lot of damage in a direct hit, and have a fair-sized splash damage radius. (Because of the splash damage, Rocket Launchers are less than ideal for close-range fighting and are notorious for causing suicides in this situation.)

Since Rocket Launchers are the most powerful standard weapon except a sniper and they have a reasonably fast reload rate and a large splash damage radius (hence the RL is called a "spammy" weapon), they are a favorite of new players. Because it's much more rarely used by advanced players, the Rocket Launcher is often found opposite the Flak Cannon in Capture the Flag, Double Domination, and Bombing Run maps, and in either wide-open or very tight places in Deathmatch or Domination. The theory behind the latter locations is that a weapon is most balanced if it is placed in a location where it is least useful; since the RL is usually considered a mid-range weapon, these locations make sense.

(The following ideas (but not the text) are mostly copied from UnrealWiki)

Use in Onslaught (UT2004 only)

 * Rockets have a lot of momentum, so they will temporarily stop or slow down Scorpions and usually change their direction slightly, disorienting the driver. Three rockets kills a scorpion.
 * Since Rocket Launchers are the second-most-powerful weapon against vehicles (factoring in their rate of fire) they are the most useful weapon to combat Goliath tanks and other large, slow vehicles (not including the Hellbender unless it's coming straight at you) after AVRiLs. However, Mantas and Raptors are usually too agile to be hit by rockets.
 * Because rockets fly very straight and cannot be shot down, they are ideal for shooting Power Nodes from a distance. A useful tactic if you're bad at aiming is to line up using the Lightning Gun or Sniper Rifle and then switch to the RL without moving.

Use in Deathmatch and other Gametypes

 * Loading up on rockets before bursting in to an area where you know there are enemy players allows you to unleash a powerful attack on multiple enemies before they know what's going on.
 * Players in the damage radius of a Rocket are lifted off the floor, preventing them from jumping or dodging. Good players can predict the landing spot and send another rocket there to greet the enemy.  This ability can also be used to boost players themselves, although the Impact Hammer (in UT) and Shield Gun (in UT2003/4) usually take this role.
 * Hitting the ground near a player's feet is easier than hitting a player because, well, it's a larger target and it's not moving. Often the splash damage is plenty to hurt the enemy.  Jumping in the air gives an easier angle from which to aim at a player's feet.