Because of this, each human contains a small amount of Furon DNA in their genetic code. Crypto is sent to Earth to harvest this DNA from human brain stems, locate and rescue his previous clone, Cryptosporidium-136, and spearhead a Furon invasion of Earth. The game is set up in a sandbox fashion. The player has a selection of weapons and mental abilities at their disposal, as well as access to Crypto's flying saucer. "Destroy All Humans!" implements the Havok physics engine, allowing for ragdoll effects on bodies and destructible environments.