Contra (Probotector in Europe) is a video game for the NES that was originally released in arcades. The game is known for its intense difficulty and brilliant two player mode. While the game was popular on the arcades, it became a household name when Konami personally ported the title over to the NES.
The character you choose will traverse through multiple platforming segments, shooting enemies on the way. If your character gets attacked once, then you'll lose a life. Once you lose all of your lives, then you'll be forced to start the entire game over. As you can see, the game is very demanding and can arguably be considered the most popular "mean" title of all time because of the dramatic challenge.
As you could assume, you'll be capable of jumping and dodging, which is clearly required in order to progress. Each character has a rifle at the beginning, which oddly (though thankfully) includes an unlimited amount of ammo. Eventually you'll find better guns, with the most popular being the split gun which shoots out three bullets in three different directions at the same time.
While the core structure of the game were based around 2D levels and combat, some portions innovated the formula by including minor 3D areas as well, though they weren't a paramouont addition.
The series has a total of thirteen video games, including Contra, though not including the remakes. Most recently Konami published Contra 4 for the Nintendo DS.
Contra is not the first game to use the code, contrary to popular belief. The game that debuted the code was in fact another popular Konami title - Gradius. The Konami code varies in the games they're found in, though they're all based around a core combination. The code found in Contra is -
Up, Up, Down, Down, Left, Right, Left, Right, B, A, START.. Once you perform this combination, the character will be rewarded thirty lives.