Fossilfuel takes players to Alaska. The action takes place on Great Sitka Island. According to the plot, one of the largest scientific centers on the planet is located there. There, scientists were able to breed dinosaurs and force them to mutate. One day, special forces enter the complex in order to capture the DNA of these creatures.

This is a sci-fi shooter. In it you can switch the camera between first and third person views. Fossilfuel has a single player campaign. There, the user, in the role of one of the employees, fights with mutant dinosaurs and soldiers invading the base. The single contains elements of horror and quest. In addition, there is multiplayer. It has co-op missions. There is also a horde mode, where users work together to destroy waves of enemies. They are attacked by crowds of giant predators and special forces.

Human bots can talk on the radio, call for reinforcements, flank targets, and determine the location of gamers by sounds (including noticing a click when turning on a flashlight). In addition, they react plausibly to the discovery of the corpses of their allies. Virtual dinosaurs have good vision and sense of smell. Some of them prefer to attack in pairs or groups. You can destroy enemies with pistols, revolvers, shotguns, assault rifles and sniper rifles. It is possible to shoot from the hip and aim through the front sight or optics.