In the video options menu, turn every option to its highest value. The announcer will say "Holy shit".
After downloading and installing the "Excessive Overkill" patch, wait until you have 150 adrenaline. Then, hold [Up] + [Left] + [Right] until the announcer says "Holy shit!" and the message "Insane!" appears across the top of the screen. You will now be berserk, invisible, and have double damage all at once for thirty seconds.