Is it normal that 13 years old boy makes weird noises (screaming, whistling, mumbling, talking in his own language) plus faces. While playing games?

Its Possible. 13 yr olds do tend to have there own language and verbalizing while playing games is not abnormal. iHowever, If this behavior extends into his regular communication with other people, or becomes random and impulsive, then he may need to be checked by a doctor for developing a condition that can be treated.
Are the behaviors. voluntary or involuntary? Does he realize he's doing them? Can he stop them? Vocal & motor tics or seizure activity only when playing electronic ( I assume) games would be unusual. I agree, investigate if the behaviors disrupt his academics, peer interaction or general behavior. Otherwise, let him know if they disrupt family functioning.