Ratchet: Deadlocked (Ratchet: Gladiator in PAL regions, also known as Ratchet & Clank 4) is a 3D platformer–shooter video game developed by Insomniac Games and published by Sony. Released for the Playstation 2 in 2005, it is the fourth game in the Ratchet & Clank series,...
The game's story begins as Ratchet, Clank, and Al are abducted and forced to compete in "Dreadzone", a violent game show in which heroes are forced to kill each other. Ratchet is given a "DeadLock" collar, which will explode if he becomes uncooperative. Ratchet defeats Dreadzone's most successful gladiators, the Exterminators, and becomes one of Dreadzone's most popular contestants. The three must find a way to deactivate the collars, and free the other heroes being held prisoner.
The gameplay is similar to other games in the series, but focuses more on shooter aspects rather than platforming. The player, as Ratchet, fights in Dreadzone tournaments across the "Shadow Sector" in the "Solana" Galaxy, with a large variety of weapons. This game was the first in the series to feature cooperative gameplay in a story mode, and also includes an online multiplayer mode. Some vehicles return from previous games, and new ones are introduced. For the first time, Clank was not a playable character.
Source: Wikipedia, "Ratchet: Deadlocked," available under the CC-BY-SA License.