In Mutant Snake, players take on the role of a genetically modified human who has grown a serpent-like body. The game begins with the player's character emerging from a swamp, where they must navigate through a series of interconnected tunnels and rooms.
The core mechanic of the game involves guiding the player's character through these tunnels, using their unique abilities to overcome obstacles and evade predators. The player must rotate the character's body to navigate through narrow passages, avoid deadly traps, and snatch food from the environment to sustain themselves.
The objective of the game is to survive for as long as possible, with the player's body growing increasingly mutated and fragile over time. The game is run directly in the browser without the need for download or registration, allowing players to jump in and start playing immediately.