Masterspy.
...What do you mean, you've never heard of it? Oh, all right, I suppose some details are in order - warning, this post may go on a bit...
It's an old (1980s) puzzle game in which you had to work out which of the four characters you controlled was a spy, by searching a set of four mazes - two of which blocked off your path as you moved through them, and the other two of which contained dead ends that could not be escaped from - to find clues. However, three types of clues were available, and only one set of clues told the truth, so by examining the clues you had to work out which set was telling the truth.
To complicate things further, all three of the loyal agents must then escape from their mazes through one of two doors in their maze, carrying a ticket found in another maze (and only one ticket may be carried at a time). The clues (at least, the truthful set) would give instructions as to which ticket would be used in which door, along with the set of 4 tickets and 4 doors that were decoys and would result in imprisonment (and thus, a quick trip to the Game Over screen). Due to the positioning of the tickets in mazes other than the door they match to, the correct order to release the characters in must also be worked out, in order to let the spy release the last agent, and then go into one of the doors in his maze to finally catch him. A save system is available, but it will be marked if you end up needing to load game to finish.
This would all be describing the mode the game refers to as "Practise"... In normal mode, the player gets 6 lives with which to survive a variety of dangers in the mazes. While these can be regained by a variety of methods of overcoming the obstacles, trying this will naturally always put you in more danger - the only real advantage is that you can now free yourself from dead ends by suicide.
Quite what I was doing playing such a game when I was 2 years old is beyond me. What's even further beyond me is what I was doing winning it - I suspect liberal use of the save system may have been involved.