Composer Harry Manfredini has said the famous "Chi, chi, chi; ha, ha, ha" in the film's score is actually "Ki, k,i ki; ma, ma, ma." It is meant to resemble Jason's voice saying "Kill, kill, kill; mom, mom, mom." So if they Composer doesnt know what he writing who else?

Voorhees' lines Kill her, Mommy, Kill her!  and took a small sample from two words, tripled them, and gave us the infamous sound bite clip!

Modern Warfare II introduces several design improvements and changes to the series gameplay, such as advanced AI systems in the campaign and co-op modes, water physics, swimming mechanics, and an overhauled vehicle system.

PlayStation 4 Cross-Gen Edition: Includes a cross-gen version of Call of Duty: Modern Warfare II playable on PlayStation 4 and unlocks a free digital upgrade to play on PlayStation 5. Please note: The game disc will be required to play the PlayStation 5 version.