In the single-player mode, the player controls a G.I. Joe training camp on the bottom of the screen protected by a barrier and armed with two laser cannons. In this mode the goal is to keep the giant Cobra-operated robot snake from destroying the shield and thus the training camp by hitting it eight times. The Cobra robot shoots venom and laser beams.
In two-player cooperative mode control of the G.I. Joe training game is split between two players as they work to destroy the Cobra robot. In the two-player competition mode one player controls the Cobra robot and another player controls the training camp.
Source: Wikipedia, "G.I. Joe: Cobra Strike," available under the CC-BY-SA License.