Sunset Overdrive is an open world action game set in the Sunset City metropolis in 2027. The player is an employee of the FizzCo corporation. At a big release party for the launch of their new energy drink Overcharge Delirium XT, the beverage turns everyone into a mutated monster. After creating a custom character the player is thrown immediately into the action. The mutants, called OD – Overcharge Drinkers, sweep the city and you need to find your way back to your apartment. Seventeen days later the entire city has been turned into an apocalyptic, yet bright and colourful wasteland. Through a number of survivors you eventually get involved with various missions and quests for different factions with large amounts of traversal through the city.
Technically the game can be played as a run-and-gun shooter, but the game encourages you in various ways to be on the move constantly. The character can run up walls or do wall runs, glide over water, and perform high jumps. Next to rails and lines hanging in the air a lot of surfaces can be used to grind to move at a fast speed. While grinding in the air it is possible to quickly switch to other rails, reverse, and change from a regular grind to an undergrind hanging from a hook. This is combined with shooting enemies. Many flat surfaces act as bounding pads, allowing you to quickly get in the air again. This acrobatic form of movement is a necessity as the groups of enemies are often overwhelmingly large. While on the ground it is possible to dodge roll, jump and strafe. Air dashes or boosts are used to get extra speed.
The game provides melee and ranged weapons, such as a crowbar, light saber and a rifle, but also sprinklers that launch acid, a grenade launcher that shoots teddy bears strapped to dynamite, freeze bombs, a gun that launches bowling balls and more. Most of these can be bought in Two Hat Jack’s shop. Weapons also level up by using them, introducing new options. Performing stylish movement combined with shooting enemies keeps a combo meter going that fills up up to four parts of style, influencing the weapons. Impressive actions are rewarded over time with badges, which can be traded in to assign overdrives, permanent, passive perks, to the characters. Further bonuses are provided through amps, modifications for the character or the weapons. These introduce for instance stun rounds or allow the character to do damage while rolling. That way players get to customize weapons by combining abilities. Up to eight weapons can be carried at a single time.
Chaos Squad is the game’s online cooperative multiplayer mode for up to eight players. It is accessed by entering a phone booth in the city where you are matched up with seven friends or strangers. There are various missions to complete and the players can vote on the objectives. While players work together, they also attempt to earn more style points that the others. The missions culminate in a large siege with many waves of mutants. Between waves you are able to put up fortifications and traps with spinning blades and walls of flames. Anything earned during a multiplayer sessions can be used in single-player afterwards.