The Konami Code is quite possibly the most famous cheat code in the gaming industry. It is a button combination pressed in many Konami games, which will unlock different things in each game. It was first used in Gradius, and has since then become a traditional code to include in future games. The code is as follows:
UP, UP, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, B, A
Games That Use The Code
Since Gradius in 1986, the code has been used in various well known series such as Castlevania, Metal Gear Solid, Contra, Silent Hill: Origins and Dance Dance Revolution. Gyruss for the NES uses the code in reverse.