Mortal Kombat 1 features a story mode, online multiplayer with rollback netcode, and offline gameplay, as well as cross-play and cross-progression, a first in the series. However, cross-play and cross-progression are unavailable at launch on Nintendo Switch, though cross-play support was added on February 27, 2024, while the King of the Hill online mode will support cross-play in the future. The game introduces a feature called Kameo Fighters, who provide assistance to the player during fights in a similar fashion to the tag assist fighters of the Towers of Time mode in Mortal Kombat 11. These characters are separate from the main roster and are chosen before each fight.
Fatal Blows, first introduced in Mortal Kombat 11, make a return. Like before, these can be triggered when a player's health drops below 30%, but this time they have the player and his Kameo Fighter delivering an attack in tandem. Additionally, the most significant attacks performed during the Fatal Blow are highlighted with effects like those seen in Mortal Kombat X's X-Ray moves.[7] Also returning is the airborne combo system seen in Mortal Kombat: Armageddon and the action spin-off Mortal Kombat: Shaolin Monks.[8]
For single-player, the game features the return of the plot-driven Story Mode and the traditional form of Towers mode from the previous games, while introducing the addition of the seasonal Invasions mode, an online mode combining fighting mechanics with board game and role-playing game elements.[9] The players are tasked with moving around the board while completing various challenges on each space they move to, earning rewards such as skins, in-game currency, or concept art for completing the challenges. Each Invasion season lasts around six weeks and has its own board and theme.[10] For multiplayer, the versus modes include Local mode to play a match on the same console, Online mode to play against opponents all over the world, and Tournament mode to host a tournament with a unified rule set for the matches.[9]
