Simply put, it counts the waves

CCTV software

You are stranded on an Island infested with zombies. Your mission is to survive as long as possible. Your weapons consist of an old submachine gun and grenades. Each zombie killed will be rewarded with ammo pickups. When grenades drop below 2, grenade pickups will appear with each kill.

This is a counter that helps you keep track of your points in the card game Δηλωτή (Diloti).