Here are some things that could make the game even better :-
1.Translate the in-game text to different languages and have a settings option.
2.Add Multiplayer where we can add friends and play with them.
3.Add more weapon options. (new guns, attachments)
4.Add different Zombie types.
5.Ability to repair broken barriers and ability to make new defences like turrets bear traps etc.
6.The aiming in the game can have different types (not necessarily but just a thought).
7.(A fun idea) Make different camera types like long, medium, close and first person.
I know making a game is not easy, these are just my opinions which i think could make the game great.Thank you for your time i hope this helps Making the game more enjoyable.🖤🖤