Contra employs a variety of playing perspectives, which include a standard side view, a pseudo-3D view (in which the player proceeds by shooting and moving towards the background, in addition to left or right) and a fixed screen format (in which the player has their gun aimed upwards by default).

During side view stages, the player can shoot leftward, rightward or upward while standing, as well as horizontally and diagonally while running.

Pressing the joystick downwards while standing will cause the character to lie down on his stomach, allowing him to avoid enemy fire and shoot low targets.

These can be obtained by destroying the pill box sensors and flying item capsules containing them, or by defeating the red-clad guards in the enemy bases.

The player loses a life if their character (Bill or Lance) comes into contact with enemies or their missiles, fails to complete a base stage before the time limit, or falls into a bottomless pit.

The player must destroy a generator at the other side of each passageway in order to deactivate the electric current preventing access.

The third stage is set in the core of the base in a fixed screen, where the player must destroy the enemy's defense system in order to expose the final target, a giant eyeball that shoots fireballs.

The seventh and final stage returns to the side-scrolling format of the first stage, as the player fights through the enemy's final line of defense (which includes a hovercraft, armored trucks, and giant helmeted soldiers) while proceeding through areas such as a snowfield, an energy plant and a hangar, to eventually reach the alien's lair, where the regular enemy soldiers are replaced with otherworldly creatures.

The player must fight a giant alien head that spawns larvae from its mouth before reaching the final target, a cardiac creature that must be destroyed in order to complete the mission.

Two commandos, Bill Rizer and Lance Bean[6][5] of the Earth Marine Corp's Contra unit (an elite group of soldiers specializing in guerrilla warfare), are sent to the island to destroy the enemy forces and uncover the true nature of the alien entity controlling them.

[8] The cover illustration of Ocean's Gryzor ports by Bob Wakelin was inspired by the then upcoming film Predator starring actor Arnold Schwarzenegger .

This version was produced in-house by Konami, and features several differences from the arcade release in order to better suit the NES's hardware.

[11] The game can be played by one or two players, but due to the graphical limitations of the NES, Bill and Lance lost their individualized character designs.

The Rapid Bullets and Barrier power-ups are also more common in this version, since unlike the arcade game, the flying item capsules now appear regardless of which weapon the player character currently possesses.

And if the player holds the select and start buttons during the credits sequence, a secret message will be displayed after the Konami logo.

[13][14][15] This was done to circumvent the BPjM's censorship laws in Germany, which prohibits the sales of violent video games to minors.

Subsequent Contra games for home consoles followed suit, all being released in the PAL region under the Probotector title and featuring similar modifications.

Beginning with Contra: Legacy of War, Konami abandoned the Probotector title and localized most of the further games with minimal changes.

[16] Rather than one-hit kills, there is an energy gauge, which allows Bill Rizer to take more than one shot or hit before losing a life.

[35] In the United Kingdom, Gryzor was a blockbuster hit in the arcades and the home computer versions topped the Gallup charts.

[36] In the United States, Contra became one of the top four highest-grossing dedicated arcade games of 1987,[37][38] and then the 1988 Nintendo Entertainment System port became and remained widely popular and remembered.

Arnie Katz, Bill Kunkel and Joyce Worley of Computer Gaming World called Contra on the NES "a truly outstanding action epic" set on a "scrolling and beautifully drawn playfield".

[34] AllGame editor Skyler Miller praised Contra, touting that the game "became the standard by which future platform shooters would be judged".

Following the success of the NES adaptations of both the original and its sequel (which was retitled Super C in its American release), subsequent sequels were produced specifically for the home console market such as Contra III: The Alien Wars for the Super NES and Contra: Hard Corps for the Genesis, becoming one of Konami's flagship series.

In April 2017, Beijing Starlit Movie and TV Culture announced they were producing a live-action film version of Contra in China.

[47] While the Konami code was first introduced with the home versions of Gradius, larger awareness of the code's existence in Konami's games grew significantly with its inclusion in the home versions of Contra (where it gave the player 30 extra lives to help complete the difficult game).