Ghosts'n Goblins (NES)

Considered one of the hardest NES games and a candidate for one of the hardest games of all-time, the NES port didn't tone down the difficult the slightest amount, and the Japanese version didn't even have continues... You feel strongth welling in your body, Return to starting point. Challenge again!

Level Select
Hold Right and press A or B or both three times. Release Right and press Up, B, B, B, Left, B, B, B, Down, B, B, B, Start. After the "PLAYER READY" screen, a number and a letter will appear. Press A or B to select a starting level and press Start to begin the game.

Hidden Credits
Complete both quests, then at the "...CHALLENGE AGAIN!" screen, press A, B, Up, Down, A, B, Left, Right and wait for the "GAME OVER" message. Instead of it, a credits screen will appear.