A Rocket Jump is a technique used in many first-person shooters where the player fires a rocket (sometimes a similar explosive device is used) at the floor, directly beneath his feet, and jumps at the proper time to propel the player far further or higher, than normally possible. This allows him to get to otherwise unreachable locations, or escape from a difficult situation very quickly. There are risks involved though. Poor timing will cause the player to be damaged or killed by the explosive blast, or a badly aimed jump can cause the player severe damage as he lands. The Rocket Jump is commonly used in tournaments and speed running challenges. Can also be performed with grenades in some games and combined with a grenade jump.
Rise of the Triad
This game was the first to contain a vertical Rocket Jump.
In one of the later levels, secret areas can be reached by rocket jumping, one bearing the message - "You sneaky rocket jumper!"
Quake III: Arena
Not only can the player use the Rocket Jump, but NPCs can use them as well.
The Rocket Jump was used in Doom as the intended way to reach a secret exit in E3M6.
The Tau cannon could be used to rocket jump.
Team Fortress 1 & 2
The Soldier class in both Team Fortress games could not only achieve a Rocket Jump but was intentionally designed to be able to do so, as shown by the soldier Rocket Jumping in game's original trailer. Not to be outdone, the Demo Man can achieve the same effect by using his mines.
Unreal 1 and Unreal Tournament series
Using the rocket jump in unreal tournament is an ideal way to get to certain hard-to-reach spots
Starsiege: Tribes, Tribes 2 and Tribes: Vengeance
Any class may use the Spinfuser to propel themselves in the air and generate more speed for skiing and flight. This was also used in an even more elaborate way in Starsiege: Tribes, where a player could throw a grenade while in flight and shoot it while it was close to rocket jump in the air.
A number of spells in Darkfall have powerful blasts, which can be used to rocket jump.