Forza Horizon 4 is a single-player and multiplayer open world racing game set in a fictionalized representation of the United Kingdom. Players join the Horizon Festival, a massive automotive event, where the objective is to race, explore, and expand their reputation across a dynamic and ever-changing environment. Unlike traditional track-based racing games, the player has freedom to drive anywhere across cities, villages, countryside roads, and off-road terrain while pursuing events, challenges, and seasonal activities.

The game features hundreds of licensed vehicles from a wide range of manufacturers, spanning everyday cars, high-performance supercars, off-road trucks, and classic models. Each car can be collected, customized, and tuned to suit different racing disciplines, including road races, dirt tracks, cross-country events, and street racing. Vehicles can also be upgraded with new parts and cosmetic options, allowing players to tailor both performance and appearance. Driving physics emphasize accessibility with optional assists, while still rewarding skillful handling and mastery of different car types.

A major innovation in this installment is the dynamic season system. The entire map shifts between spring, summer, autumn, and winter, with each season introducing distinct weather conditions, road surfaces, and challenges. Frozen lakes open new paths in winter, muddy trails emerge in autumn, and summer festivals highlight fast-paced road events. These seasonal rotations affect not only the environment but also event availability and vehicle selection, encouraging adaptation and strategic use of a diverse garage.

Progression is tied to Influence, a system that measures the player’s reputation across multiple activities. Completing races, stunts, exploration objectives, and showcase events builds Influence, unlocking new areas, vehicles, and opportunities. Showcase races provide cinematic challenges, such as competing against trains, planes, or hovercraft. Exploration is also rewarded, with hidden barns containing rare vehicles, speed traps, drift zones, and danger sign jumps scattered across the world.

Multiplayer is tightly integrated through the shared world system. Up to 72 players can drive together on a single server, synchronizing seasons and events for all participants. Cooperative convoy play allows friends to team up in races, while competitive modes include online championships and ranked races. Players can also design and share custom routes through the route creator, adding to the variety of content. Offline play is supported, replacing human players with AI-controlled Drivatars.

Additional features reinforce immersion in the festival setting. Houses scattered across the map can be purchased to serve as player hubs, unlocking perks such as fast travel options or customization bonuses. Character personalization is included, with clothing, emotes, and accessories earned through gameplay. In-game credits can be spent on cars, upgrades, properties, and cosmetic items, while wheelspins provide randomized rewards. The game also incorporates a photography mode, leaderboards, and creative challenges that highlight community-driven content.