You are playing Nightwalkers.io
Nightwalkers.io or in short, Nightwalkers, is a free Co-Op browser zombie survival game from JeFawk Games. It features unique gameplay elements such as Apocalypses and Noise which attracts zombies.
Grab a friend and make an invincible base. Gather resources and build weapons, fight through endless waves of zombies to establish a new World Record…or don’t and just chill in the base and talk to one of the 1000+ daily people on the chat.
However you play is up to you, but don’t forget, kill as many zombies as possible!