This game really wants for a way to fight the zombies. They feel like they have a tendency to camp the return portal so you have to save stamina to tank damage from them.
Somehow it reminds me of Neopets? Not sure if that's just a me thing. It's kind of a cookie clicker if you think about it. You collect material to upgrade things that let you collect more material, but with an added requirement of requests from the wishlist.
I would probably have spent more time on it if it weren't for the zombies being immortal douchebags.