  In combinatorial game theory, the winning player for a position in normal
play is analyzed and characterized via algebraic operations. Such analyses
define a value for each position, called a game value. A game (ruleset) is
called universal if any game value is achievable in some position in a play of
the game. Although the universality of a game implies that the ruleset is rich
enough (i.e., sufficiently complex), it does not immediately imply that the
game is intractable in the sense of computational complexity. This paper proves
that the universal game Turning Tiles is PSPACE-complete.
