The secret knowledge quickly spread by word of mouth, and by the time Contra was released, the code became almost a tradition.

However, as with many cheat codes of that time, the developer just forgot to remove it from the final release, and soon after curios gamers discovered it.

The sequence was easy enough to remember for testers and simultaneously sufficiently hard to enter accidentally during the gameplay for unsuspecting users.

The mistake was discovered after the release, but developers decided to leave it there, as removing it could result in new bugs and glitches. After entering the sequence using the controller when the game was paused the player received all available power-ups. One of the game’s developers, Kazuhisa Hashimoto, decided that the game was too difficult, so he included a loophole to help the testers. The code was first used in the 1986 release of Gradius, a cosmic-themed shooter for the Nintendo Entertainment System. It is widely believed that Contra was the first game to feature the code, but the truth is that it appeared earlier. Eventually, it became so popular that TV shows featured it, and websites added it as an Easter egg for curious users to find. Let’s unveil the mystery – this code is a cheat sequence that can be utilized on most Konami games (hence the name), as well as some other projects. Well, it’s time to figure out what this mysterious symbol pattern means and how it can be used. Or maybe it appeared in a TV series, but you missed the reference since you have never played anything designed by Konami. Welcome to the legendary Konami Code! You have probably seen this mysterious symbol streak ↑↑↓↓←→←→BA (up up down down left right left right ba) on T-shirts or mugs of your geeky friends, wondering what it meant. Konami Code | Full Supported Konami Video Games List

Contra nes cheat codes