A single-player video game is a video game where input from only one player is expected throughout the course of the gaming session. A single-player game is usually a game that can only be played by one person, while "single-player mode" is usually a game mode designed to be played by a single player, though the game also contains multi-player modes.

In tabletop games and video games, game mechanics are the rules or ludemes that govern and guide the player's actions, as well as the game's response to them. A rule is an instruction on how to play, a ludeme is an element of play like the L-shaped move of the knight in chess. A game's mechanics thus effectively specify how the game will work for the people who play it.