Game semantics is a trace-like denotational semantics for programming
languages where the notion of legal observable behaviour of a term is defined
combinatorially, by means of rules of a game between the term (the "Proponent")
and its context (the "Opponent"). In general, the richer the computational
features a language has, the less constrained the rules of the semantic game.
In this paper we consider the consequences of taking this relaxation of rules
to the limit, by granting the Opponent omnipotence, that is, permission to play
any move without combinatorial restrictions.