Thank you for the thoughtful comment!
Yeah, I had some trouble trying to decide how to express the mechanics to the player. I started off with a set of instructions on the title screen, but I know most people like to just jump right in, so I erred on the side of just throwing the player straight into the fire... or, well, the water, hahah.
I was hoping that placing the two zombies that get killed at the beginning would be sufficient to illustrate how safe zones work, but that does happen pretty quickly, so I can see how that information could be easily lost.
I think if I had had more time, I would have added a really big indicator that a player is safe, like a glowing shield hovering above them head when they're in a safe zone.
I'm playing with the idea of rewriting this game altogether - since I only had 3 days to make it, I had to skimp on a lot of things. But I am proud of how the mechanics are actually legitimately fun to play for their own sake, and I think I could do it much, much better if I spent some more time on it.
If I do rewrite it, I'm definitely going to prioritize clear communication of the safe zone and water mechanics.