From The TimeSplitters Wiki

Brown Zombie
Unlocked by	Challenge > 1-B Putrid Punchout
Species	Zombie
Size	Normal
Accuracy	N/A
Agility	N/A
Stamina	N/A
Fire Proof	N/A
Shock Proof	N/A
Default AI	N/A
Native TimeZone	1935
First Appearance	TS1 Story Mode
Relations	Green Zombie, alter-ego
Games	TS1

Brown Zombie is a generic zombie, who doesn't look brown contrary to his name. His alter-ego, Green Zombie, shares his characteristics and appearence except from which he is inversely arranged (brown zombie's eye is on the left, green zombie's is on the right).

TS1 Gesture	Gets up from the ground whilst grunting.	TSFP Gesture	N/A
TS2 Gallery	N/A	TSFP Gallery	N/A