But is very easy to stagger when aiming at its head. Mr.X is invulnerable on all of his bodies. You will have help from your AI creatures when you punches the survivors to death. Try to spawn Mr.X between creatures/traps and the survivor, so they have less places to escape.
although with some practice you will be able to catch those annoying survivors off guard with the Bull Rush attack (right click) and make them waste their resources and ultimate skills with Rampart (E)! Mr.X has been known to be juked in door frames quite a lot because of its passing door animation. Mr.X is stunned much longer than G.Birkin but in exchange, he can block the flashes and bullets with his Rampart (E) skill. Here are all the controls for playing Mr.X that I had to figure out by myself and with tests with my brother. you get out your 'high risk of dismemberment, killing machine!' then everyone jukes you and taunt you.