The Uncanny X-Men Trivia (NES)
Last level codeThe code to access the game's last level was printed on the front of the game cartridge:
"+B+Up together with Start"
However, the code printed is only half the required command. The full code is, "Select+B+Up then press Start", but the first part could only be seen by completing the other stages fulfilling a secret condition (killing 30 special enemies). This causes the game to display hidden messages in the post-stage text, detailing the code and its purpose.