Random lift shafts, random rooms, digitised speech (this was a big thing in the mid-to-late 80s).
The title is misleading, I completed it at least 50 times.
Jump over an enemy-robot, search an object, get outside to see if your search was worthwhile... Search all of the rooms (and I think on any given playthru it only ever showed 70% of the rooms), piece together a (literal) jigsaw and meet the bad-man.
Lives? Nah, homey, the best games don't roll like that... If you died - zapped by a robot, or fallen down an abyss - the game took minutes off the time you had to get the pieces to complete the puzzle, then your agent would regenerate.
Simple and perfect. Platform game Heaven.
All Impossible Mission variants are poop.