When the game describes for the the player what happens. IMO, most of
the complexity in inflected languages would be on the output side, to
ensure that all messages the game prints are grammatically correct.
> throw ball at monkeys
> The monkeys play with the ball for a while.
It that would be translated to Russian, the game has to know the
instrumental case of the object thrown (the ball in this example).
Verb conjugation would in pratice not be much of a problem; only in
past tense if the subject isn't known beforehand.
BTW, Jigsaw, with the unknown genders of the player and Black, would
be difficult to translate into Russian. Any sentence in the past tense
with Black (or the player) as the grammatical subject would reveal
the gender (the verb ending would tell).
-- Bjorn