In Jurassic Park: The Game, the T. rex is referred to by Billy Yoder as Rexie, a name similar to her novel counterpart. She first appears in the game attacking the Triceratops Lady Margaret in the chapter "Triceratops Trouble" and her last appearance is at the end of the game in the chapter "Old Friends".
Attack on Lady Margaret
Sometime during the night of the tropical storm, after escaping her paddock, the T. rex began wandering farther from her paddock area. As Dr. Gerry Harding and his daughter, Jess Harding, were heading for the boat to the mainland after Gerry returned to the site of the sick Triceratops to pick up Jess in his gas powered jeep, they found Nima Cruz, a corporate spy who went to search for Nedry after he failed to arrive at the East Dock. As the three made their way, they come across Bahkita, an infant Triceratops that was out of her paddock. They managed to get the dinosaur back into her enclosure, but Lady Margaret, the alpha female, appeared and attacked, which also attracted the Tyrannosaurus rex. The group barely managed to escape, hiding in a maintenance shed as the dinosaurs fought and decided to spend the night inside. It is unknown what was the outcome of this fight, but it is known that the T. rex survived and that Lady Margaret lost a horn.
Return to the Visitor Center
After killing the raptors in the Visitor Center, she briefly left said center but returned when Dr. Gerry Harding, Jess, and Nima Cruz reached the Visitors Center, unaware that Hammond and the surviving members of InGen's endorsement team had had just recently fled the island. While the humans were inside, Dr. Harding spoke with Dr. Laura Sorkin over the radio, who helped cure Nima of her ailment caused by a Troodon bite. The T. rex attacked once again, forcing the trio to avoid her as best they could while Gerry tried to stop Nima from shaking and Jess used the center's pillars to stay hidden. To get the Tyrannosaurus rex's attention, Gerry dropped a box that hit her back. Jess grabbed the tranquilizer darts and ran upstairs to help Gerry where they healed Nima. The T. rex proceeded to follow Jess up the stairs, but at the last second, the staircase collapsed, causing the T. rex to wipe out and crash to the floor. When the Tyrannosaur regained balance the vibration of her feet caused Jess Harding to fall while the Trio was escaped just outside on the roof.
Even though Jess caught a ledge preventing her falling to her death, she soon lost her grip and fell further down, now hanging onto the door frame. Dr. Harding came down from the roof to help her though soon the Tyrannosaur charged through the doors knocking Dr. Harding back. The predator then tried to kill Jessica as she dangled from the door frame. As Dr. Harding grabbed his tranquilizer gun, Jessica finally lost balance and landed on the top of the head of the T. rex, which prompted the Tyrannosaur to shake Jess off her head. Nima, fully recovered now, tossed the tranq darts to Dr. Harding who shot the Tyrannosaurus in the face three times, saving Jess from potentially being eaten. However, the T. rex's retaliation was quick and she soon charged through the door frame, destroying it. She then proceed to attack the tour vehicle that the Hardings were behind using as shelter. The Tyrannosaur's attack on the Harding finally came to an end when Dr. Harding told Dr. Sorkin to start the tour vehicle, which distracted the T. rex.
After a second mercenary team landed on the island to rescue those who had been left behind and retrieved the survivors, the group headed back to the helicopter, but found that the mercenary Daniel Cafaro had disappeared. The Tyrannosaur reappeared and made her way towards them, forcing Oscar Morales to fix the chopper himself. She finally reached them just as they managed to get the helicopter working again. As the helicopter was taking off, she nudged it, causing the aircraft to swerve, but Yoder ultimately piloted the helicopter to safety and evaded the T. rex.
Encounter with Nima and Billy
Then, after Jess helped Dr. Sorkin in the Parasaurolophus Enclosure, Nima got into a fight with Billy Yoder, who was sitting in a tree, the T. rex appeared again, chasing a Parasaurolophus, and then Yoder almost fell but grabbed a branch in order to save himself. The Tyrannosaurus rex, having noticed this, picked up a piece of helicopter wreckage with her mouth, and launched it at Yoder in an attempt to knock him out of the tree. Yoder let go at the last second and landed hard on the forest floor. Then he and Nima began to run away from the T. rex and she followed them into the Parasaur Paddock. Inside, the Tyrannosaur became distracted with a Parasaurolophus carcass and briefly during the feeding killed a Velociraptor that had been eating the carcass as well. Yoder immediately returned to the paddock to retrieve the Barbasol can he had dropped when he was in the enclosure, thinking that the T. rex would be too distracted with the freshly killed Parasaur carcass. But just as he was about to pick it up, his nervous movements caught the Tyrannosaur's attention. At that very moment, Yoder then attempted to be nice, and tried to sweet talk his way out of being eaten. Realizing this wouldn't work, he grabbed the embryos and ran. When the Tyrannosaurus was just about to grab him, Nima shut the door to the Maintenance Tunnels in the large predator's face.
She confronted the group one last time during the conflict between the Nima and Billy. The Tyrannosaur stalked into the shipping yard forcing all four of the humans to freeze in their positions. The Tyrannosaurus rex started to sniff at Jess when her father gently nudged the cryocan with his foot causing it to roll toward the dock’s edge. In a momentary lapse of judgment, Yoder scrambled to save the can before it fell into the water. Although he had saved the can, he had caught the attention of the large theropod. The T. rex only hesitated a moment before she engulfed the man with her jaws and lifted him in the air to consume him. Yoder dropped the can. With the T. rex's back turned to them, Nima raced to retrieve the can, the Hardings followed closely behind. The Tyrannosaur was alerted by the movement behind her and chased after them. Nima and Jess squeezed into shelter while Dr. Harding was left outside.
Dr. Harding then attempted to distract the T. rex in order to keep its attention away from the two ladies. The T. rex damaged the bridge platform the pair was standing on flinging Jess over the edge. She managed to keep herself from falling off the bridge together but was dangling mere feet from the Tyrannosaurus. She pleaded for Nima’s help and was saved from the jaws of the predator at the expense of the cryocan that was crushed by the approaching Tyrannosaurus. Dr. Harding, while the Tyrannosaurus had turned to face Nima and Jess, grabbed a steel pipe. He swung the pipe into the leg of the Tyrannosaurus, successfully gaining her undivided attention, thus allowing his companions to escape to the last remaining boat at the end of the docks. Dr. Harding scrambled through the container yard, the large theropod hot on his heels. Dr. Harding eventually found cover inside a cage. The T. rex could not reach the man with her jaws due to the small opening at the end that was suited for caging smaller, man-sized dinosaurs. Frustrated, the dinosaur thrashed about and finally flung the cage toward the pier that the small boat was located.
Dr. Harding noticed that he was less than a one hundred meters from salvation, he scrambled to his feet and sprinted for the boat that his daughter was pull-starting. The T. rex stalked through the gate that separated the pier from the container yard. The theropod was nipping at Dr. Harding for the final stretch. As he neared the end of the dock, he jumped onto the moving boat as the dinosaur made one last effort to grab him. The boat successfully swept its three passengers away from the outraged Tyrannosaur that bellowed loudly after the boat.