Usually, metagamers are considered the elite gamers, who usually have been playing the game
for the longest time period, and have the most skill and play the most competitively, the
metagame is the environment that these competitive metagamers play in, in any given game, and the strategies used by those top competitive players.
The metagame is usually much more narrow then casual gaming, and there is often very little variation in strategy between metagamers because only the best are used.
Metagame often involves strategies found or created by players, not just simple tactics designed by the game developers to intentionally be part of the game, while also playing by the standards other metagamers believe to be commonplace.
Games such as
mario bros or
freeze tag usually lack a metagame, because the multiplayer aspect is limited, and/or there is little to no strategy or skill involved in the game, simple games in general usually lack or have a very small metagame, while more complex and competitive games usually have a larger metagame and a larger gap between strong and weak players.