The metagame refers to the collective decisions that are made outside of a game that affect tournament play. A metagame is said to have a "shape" or "state" which refers to the commonly employed practices and strategies in tournaments. In Smash Bros., the most basic decisions that give form to the metagame are the player's decisions on what characters to use and what stages to practice on. More complex decisions include deciding on what character and stage combinations will counter the most popular characters and styles.
Metagames typically continuously evolve and developing the metagame involves deciding what strategies to use or alter that can most effectively counter others in tournament play. If a metagame does not evolve or becomes overly centralized around few strategies, competitors may start to find the game boring and tournaments will suffer a lower turnout. Competitors tend to be vocally dissatisfied until the tournament rules are remedied. For example, one of the commonly cited reasons to ban Meta Knight from tournament play is the frustration he causes among competitors because of his overwhelming dominance in Brawl tournament results as well as his overuse as a main character.
Decisions that form the metagame generally do not include those on what should be tournament legal, although each usually influences the other. For example, what stages are legal may greatly influence character viability. Stage lists that do not include hazards that hinder less mobile characters, such as the panning camera and obstacles on Rainbow Cruise, may produce tournament results that include more characters that are less agile. If the stage list includes Onett, which greatly favors Fox and Falco in Melee, it may lead to greater use of those characters.
Different levels of skill may feature their own metagame state because the viability of different strategies and decisions depends on how deft and knowledgeable the opponents are. For example, Jigglypuff in Melee may be considered one of the worst characters in the game by less experienced players because of their inability to properly exploit its overpowering aerial game and successfully land Rest, as well as the fact it's KO'd extremely early, making it very difficult for inexperienced players that can't evade properly to survive for long with it. Conversely, Ike in Brawl is considered just a middle tier character by more experienced players because his very slow attacks and inability to handle opposing camping well makes it difficult for him to compete with high tier characters, while less experienced players tend to consider Ike extremely overpowered because their lack of knowledge on how to exploit Ike's slowness and own slower reflexes leads to them getting easily hit and KO'd very early by Ike's extremely powerful attacks.
Routine analysis of the metagame has allowed the community to draw conclusions about the relative performances of playable characters in Smash Bros. games, and publish them in the form of character tier lists. Each tier list evolves alongside the development of the metagame it references, and is updated as significant changes occur.
Examples of changing metagames in the Smash series
Being the first game in the series to be split between two consoles, routinely introduce balance patches, and add new characters via DLC, the metagame of Super Smash Bros. 4 has shifted greatly by external influence. Examples include general perceptions of characters' strengths and weaknesses after updates.