In Prototype, "the player controls the character of amnesiac Alex Mercer in New York City, with freedom similar to that of the Grand Theft Auto series and some Spider-Man games, in which the player can visit most locations and interact with the environment while not engaged in missions."

A key aspect of Prototype is the 'disguise or destroy' concept, which is tied to Alex's enemy-consuming and shapeshifting powers. Alex can also shapeshift into more fantastic forms for attack, defense, or sensory enhancement. All of these together are intended to give players multiple ways to complete their objectives. Movement is simplified to allow more controls dedicated to shapeshifting, with Alex automatically navigating obstacles in a manner inspired by Parkour.

Source- http://www.techeblog.com/index.php/tech-gadget/video-new-prototype-xbox-360-ps3-screenshots-developer-diary-released