"Another visitor. Stay a while. Stay forever! Muhahaha"
That are the introductionary words to one of my youths greatest obsessions, to solve the mystery of Impossible Mission 2.
The thing about IM2 is that its so rich of information, and of puzzled that you get all befuzzled. You got 3 hours to solve them all, and in your path you find tools as bombs you can use to get past some of the trickier parts.
I don't think I ever solved the long mystery of Impossible Mission 2, but it gave me many hours of pleasure looking for clues and opening locked doors with tape recorders.