I play once a month now,my clan does the same.Like others have wrote,u need to spend real $$$ on it,it not worth it!! When they have big zombie event,unless you have best weapons,u won't stand a chance!! If u do level 1,u won't get much,3,4 does,but level 1,u can kill them very easy,then at level 3 &4,you can't,unless u keep up grading your town center,u can't upgrade your guns!! That make alot of sense!! In the videos it makes it seems like npc will helping u,no you are alone!!