This is a fairly common question on this forum, if memory serves me correctly. My friends also often play games and they sometimes have some kind of problem with the keyboard. I work in a service center and fix various computers and keyboards as well. So I can tell you that there is a good chance that this problem is caused by mechanical damage to your keyboard. Can it be that you spilled something on it? Better as for me to protect myself and buy a keyboard cover silicone, so this does not happen again. I also advise to take your keyboard for repair or even buy a new one. Good luck to you!