Features
- Start with infinite lives
- Keep weapons after losing a life
- Become invincible-- enemies don't shoot at you
- Start new life with machine gun

Description
The player controls one of two armed military commandos named Bill 'Mad Dog' Rizer and Lance 'Scorpion' Bean, who are sent on a mission to neutralize a terrorist group called the Red Falcon Organization that is planning to take over the Earth.

The main character is equipped with a rifle with an unlimited amount of ammunition. The player can also jump, move and fire in eight directions, as well as move or jump simultaneously while firing. A single hit from any enemy, bullet, or other hazard will instantly kill the player character and discard the current weapon. There are over 10 areas in the game. There are two types of stages in Kontra.

In addition to the standard side view stages, Kontra also features stages in which the player character is seen from behind and must move towards the background in order to proceed. Each of these '3D maze' stages are set inside the corridor of an enemy base in which the player must fight through the base's defenses in order to reach the core of the base. During the 3D maze stages, the upper screen will display a map of the base along with a time limit. Each maze stage is followed by a '3D fixed' stage set at the core of the base, in which the player must destroy a series of flashing sensors to expose an even larger sensor and destroy it. Kontra also features a two-player cooperative mode. Both players occupy the same screen and must coordinate their actions. One player lagging behind can cause problems for his partner, as the screen will not scroll onward, and a slow player can be fatal to his partner. The European release, Gryzor, does not feature a simultaneous 2-Players mode. Instead, both players take turns: whenever one player dies, the other gets his turn.