A secret 4-digit code is behind the door -- no digit repeats.
Each guess tells you how many digits are in the right place,
how many are in the secret but the wrong place, and how many
aren't used at all -- never which ones. Crack 3 doors to
win -- 20 guesses per door. Door 2 gives you 90 seconds per
guess, door 3 gives you 45 -- run out of guesses OR time and
it's ACCESS DENIED.