"Star Trek: Shattered Universe is a Star Trek video game set after the original series episode Mirror, Mirror. It was released for the Xbox and PlayStation 2, and received almost universally poor reviews.
In the game, Captain Hikaru Sulu and the crew of the USS Excelsior swap places with the crew of the mirror universe ISS Excelsior as a result of a localized stellar ion storm. They are hunted by Mirror-Chekov, who commands the ISS Enterprise, and assisted by the Klingons and Romulans. During their trek home, the Excelsior crew encounter mirror universe variations of the original series' missions, including the M5 multitronic computer (The Ultimate Computer), Balok, (The Corbomite Maneuver) The giant space amoeba, (The Immunity Syndrome), and the Planet Killer (The Doomsday Machine).
While the game takes place at some point during the era of the Star Trek films, it is unclear exactly when. The Enterprise has not yet been decommissioned (despite the fact that the order to return to Spacedock for decommissioning was given on Stardate 9529.1-this is in the short scene in 'our' universe-and Sulu's first log was on Stardate 9585.9), but Sulu is in command of the Excelsior, placing the game somewhere in the timeframe after Star Trek VI: The Undiscovered Country. However, in the mirror universe, Spock has not yet completed his coup d'état -- the Empire contacts Mirror-Chekov several times during his mission to capture Sulu -- but there is still much time for that to occur in the mirror universe timeline. However, James Kirk is nowhere to be seen."
Source: Wikipedia, "Star_Trek:_Shattered_Universe," available under the CC-BY-SA License.