fist indicates something that must be destroyed, while a blue shield indicates something that must be protected. Samson's base is indicated by a green house icon. The Hulk is capable of jumping great distances, running up and along walls, and climbing, as well as a series of basic attacks and grapples to use against enemy characters. The Hulk can grab several objects and use them as weapons, such as wielding a lamppost as a club. Larger objects such as cars and tanks can be picked up and thrown to dispatch groups of enemies from a distance. The Hulk's health is represented by a bar on the upper-left corner of the screen, while a second bar below it increases whenever the Hulk takes damage or destroys property. When this bar is filled, the Hulk enters a "critical mass" state in which he is capable of his most powerful and devastating moves. However, using these moves depletes the bar, causing the Hulk to drop out of critical mass. When his health drops to a certain level, the Hulk will enter an "adrenaline surge" state similar to critical mass, in which he can use the same moves without depleting the critical mass bar. If the Hulk causes wanton destruction during the free-roaming gameplay, the spokes of an "emergency response meter" on the upper-right corner of the screen will extend. When the meter's center lights up, a military strike team will be dispatched to combat the Hulk. Accomplishing missions, destroying property, and defeating enemies earn the Hulk "smash points", which can be used to purchase new moves at Samson's base. Such moves include new ways to weaponize objects, such as using two halves of a car as steel gloves, or using a flattened car as a shield. Each mission that is completed unlocks additional moves to purchase. Some moves have dependencies, and will not be available until the moves they are based on have been purchased. Hidden throughout the world are sixty collectible comic book covers from the Incredible Hulk series that unlock a variety of rewards, including artwork, skins, and cheats. Plot Scientist Bruce Banner has spent years in semi-isolation researching a potential cure for an affliction that transforms him into the Hulk when he is angered or stressed. He has created an experimental device intended to modify his subconscious and repair psychological damage inflicted upon him by childhood trauma, thus subduing the