That was fun! The headshot mechanic made killing zombies really satisfying and the sound effects and graphics created a cool creepy atmosphere. The voice acting was a little dispassionate though lmao
One thing that could be improved is the visibility. The darkness and the low precision shader made it really hard to see zombies, especially their head and limbs. It took me a while to notice you could shoot limbs off because of the poor visibility.
Also, since the robot says their scanners have picked up survivors, it would make sense to give the player some hint that guides them to the survivors. Maybe a handheld device like a compass that points to the closest survivor, or a minimap or something.