Instagib

Instagib is a mutator featured in all Unreal games with a multiplayer aspect except for XMP. One could argue this is the mutator that has the biggest impact on gameplay of all official mutators.

In an Instagib match all players start with an Instagib Rifle, a weapon that kills any enemy player with just one shot. All other weapons and ammo are removed from the game, as are pickups, although players may still be equipped with a Translocator. The Instagib Rifle cannot be dropped.

Weapon
The Instagib Rifle is traditionally a modified Shock Rifle, although in Unreal Championship 2 is is a modified Sniper Rifle. In either case it will still function as a hitscan weapon. The weapon is changed to no longer require ammo, meaning it has an infinite amount of shots.

Instead of the usual blueish-purple beam, a powered up Shock Rifle will shoot a red beam or, if used on the blue team in UT2003 or later, deep blue beam. The weapon's alternate fire will function in exactly the same way, except in the case of Unreal Tournament's Assault gametype, where only the alternative fire can destroy objectives. In the case of a powered up Sniper Rifle alternate will allow its user to zoom.

Depending on the game and mutator, the Instagib Rifle's beam is either stopped as soon as it hits an enemy player, or will burn right through every player it encounters, allowing instant Multikill awards. In the original Unreal Tournament the beam caused a small explosion at its point of impact. In Unreal Tournament 2003 and 2004, the weapon can be used with a sniper scope as alternate fire, making it utterly unstoppable at long range in the hands of a skilled sniper.

The Instagib Rifle does a lot, but not an infinite amount of damage, making it possible for characters with a lot of health to survive being hit, though this doesn't feature in the regular game. In UT2003 and 2004, using the Booster adrenaline combo to increase health and shield power to full can make the player survive a single hit (because damage is only 300 points). In the original UT, this is completely impossible, as the weapon deals somwhere around 16500 points of damage.

Usage
Instagib is typically used in the Deathmatch, Team Deathmatch, Domination, Double Domination, Capture the Flag, and Last Man Standing gametypes. It can be used in Invasion and Mutant, though the huge fire power defeats the challenge in defeating a superior force.

It is not possible to use the official Instagib mutator in the Assault, Vehicle Capture the Flag, Onslaught, and Warfare gametypes, though unofficial versions have been made by fans. In addition, one can spawn the weapon in UT2004 using the summon xweapons.supershockriflepickup command in the console.

Strategy
Because of the Instagib Rifle combines a slow reload time with huge firepower, both your and your enemy's reload time are much more important than in normal games.

It is not uncommon to see two beginning Instagib players enemies dancing around each other taking shots in turn, because they are simply holding down the fire button. Enemies that do this are easy to avoid getting killed by, simply by realising the shots happen in a set "rhythm", making them easy to dodge away at the last split second.

A better way at using the Instagib Rifle is by waiting firing until you are sure your enemy is exactly in the path of your Instagib beam. (Due to all players' high mobility, sometimes this isn't an exact science.) One benefit is this is generally easier to accomplish than trying to line up with enemies at the rhythm of your weapon with the trigger continuously held. Another benefit is that this makes you much less predictable. Since your enemy won't know exactly when you will fire, making it harder for him to dodge away at the right time.

If you encounter an enemy that holds the trigger, you can time when to concentrate on avoiding his fire, and use the periods of time between his firing to return fire without having to worry about being hit by that player.

In general it is advisable to avoid running in straight lines, especially in long corridors, since enemy players at either end won't have to adjust their aim much to hit players coming straight towards them, or running straight away from them. This concept is called Enfilade. For the same reason you should Dodge Jump and Double Jump (in applicable games) with care.

Because being hit just once means dying no matter how much health you have, taking a little falling damage or having fallen into damaging slime have no impact on the game, unless you already had little health.

Zoom Instagib
In 2003/2004, there's a special variant of the Instagib mutator, called Zoom Instagib, whose alternate fire is a zoom function like that of the Lightning Gun. It's inspired by the third-party UT mutator of the same name.