  We study the computational complexity of computing or approximating a
quasi-proper equilibrium for a given finite extensive form game of perfect
recall. We show that the task of computing a symbolic quasi-proper equilibrium
is $\mathrm{PPAD}$-complete for two-player games. For the case of zero-sum
games we obtain a polynomial time algorithm based on Linear Programming. For
general $n$-player games we show that computing an approximation of a
quasi-proper equilibrium is $\mathrm{FIXP}_a$-complete.
