Okay, my first view is that zombs.io is a multiplayer survival game. Very complex seemed to me. But then I realized that this is a basic and funny defense game. You aim to collect resources, build defense and be ready for the night. Because zombies attacking you in the night as mass. Ahh, also you should be aware of other players. Because anyone would attack your base. Graphics is normal for this game, leaderboard ok, chat ok but the difficulty is very easy for me.
If you want a funny defense game, zombie.io is ideal for you.