Super Smash Bros. Ultimate is a platform-based fighting game that unites characters across Nintendo and third-party franchises in highly dynamic brawl arenas. It serves as the fifth main entry in the Super Smash Bros. series, offering the largest roster and stage collection in the franchise.

Gameplay retains the series' core mechanics: players battle by inflicting damage (indicated as a percentage) to increase knockback and ultimately eject opponents from the arena. The game supports up to eight fighters simultaneously in modes like Time, Stock, and Stamina battles, and includes both single-player and multiplayer options. A wide range of modes - from Classic and All-Star to the adventure-focused World of Light - complement local and online competitions.

Ultimate also includes the complete return of every fighter from previous entries - an unprecedented feat reflected in the tagline "Everyone is here!" - alongside extensive stage representation across gaming history. The game introduces Spirits as collectible enhancements, flexible rule customization (like choosing Battlefield or Omega stage variants, preset rulesets), and advanced techniques like directional air dodges, perfect shields, and short-hop attacks that deepen competitive play.