I really like the idea of building your own walls to create barriers to zombie hordes. As I had to aim forward it was difficult to shoot them as I couldn't move away and shoot, this lead me to make myself a box and I got stuck and couldn't get out :( maybe wall HP for if you've walled yourself in so they can still get you or you being able to remove them would create more interaction with the wall mechanic? it's a really cool concept to create your own zombie maze and strategize out how to keep them at bay the longest!