Rubicon's plot deals with a catastrophic nuclear accident in Russia. The player must trek through seven levels inhabited by mutated super-intelligent animals in order to diffuse each nuclear reactor. Gameplay is a Gryzor style flip-screen run'n'gun shooter (with occasional jetpack flights), with fairly unrelenting action. Power-ups are issued by a canister which the player will have to control in order to gain the weapon they want. The difficulty level is pitched high, as with Project X which was released at a similar time.