Mortal Kombat 1 has been confirmed to feature a story mode, online multiplayer with rollback netcode, and offline gameplay. The game introduces a feature called Kameo Fighters, which provides 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 will be separate from the main roster, and chosen before each fight. There are two types of assists provided by each kameo fighter, Summons which can be performed while the player remains in one place and Ambushes which can be performed regardless of what the player is doing. They can also be called to perform their own Fatalities and Brutalities. In addition, the chosen kameo fighter also affects how much health the players will have in a fight.^[4]^[5]

Fatal Blows, first introduced in Mortal Kombat 11, return with different functionality. These special moves can still be triggered when a player's health drops below 30% only, however in this game they are performed as collaborative offensive moves between a player and a kameo fighter, with each delivering an attack in tandem. Additionally, the most significant attack performed during the Fatal Blow features the X-ray effects last seen in Mortal Kombat X.^[6] Also returning is the Air Kombat combo system which was featured in both Mortal Kombat: Armageddon and the action spin-off Shaolin Monks, and is being refined for this game.^[7]

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 introduces the addition of the seasonal Invasion mode, an online mode combining fighting mechanics with board game and role-playing game elements.^[8] The players are tasked to move 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.^[9] 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.^[8]