Crysis 2 - nanosuit arm cramp
4A strange but so far not very useful glitch.
Enter the upgrade-menu as you're trying to pick up a weapon. Timed correctly, Alcatraz will drop off his previous weapon right as the menu appears. After leaving the menu, you're now in NoWeapon mode (or this is the term the customization menu gives you if you open it).
It's basically an unique mode where you have nothing in hands, can't aim, can't sprint and can't melee. You can however pick up enemies or objects. Just switching weapons returns things back to normal.
The reason I think it's a glitch is because if you try to enter upgrade-menu while in NoWeapon, some strange things can happen. One reaction is that the upgrade-menu appears without the graphics or Alcatraz's arm. Well, nothing much to it, it's basically the same as the upgrade-menu, only more obtuse.
Another, more interesting reaction is that Alcatraz sometimes puts out his arm without the upgrade menu activating. This is the arm cramp the video title refers to. You can continue playing like normal with your arm stretched out pointlessly! It's basically another unique mode. Can't aim, can't melee, can't pick up enemies or objects, but you can sprint and do power slides. Customization menu doesn't have any name or data for the arm.
Falling into a deadly pit worked differently in this mode. Alcatraz actually landed at the bottom instead of instantly dying. Too bad this didn't help break long falls anywhere else.
Playing like this, the viewpoint always focuses on the arm, making the background blurry and unpleasant to look at. You are completely powerless when encountering enemies! Climbing or doing air stomp returns Alcatraz to NoWeapon-mode where you can at least grab enemies, giving you some degree of offensive without ending this entire glitch outright.
And... that's what I got so far. It might be interesting to see if the arm cramp can carry over into cutscenes or such.