Cool game! The music, sounds and visuals are very fitting! Though shooting zombies in the dark felt a litle jank without being able to see them and sometimes I felt like i shold've hit them when I didn't. If you don't want people shooting zombied in the dark then make the health bar invisible until zombies enter the light. But if you want people to still try to shoot zombies in the dark a good solution is an outline shader as Inkbuddy pointed out!