All you need to Do is Type "How to bhop in css" in Google and learn it in few days
Learn how to Beat the Bhopers :
Whenever You are defending Throw nades in front of zombie not behind them to boost them
and also you can Shoot them Back if you noticed, when you see them they are getting speed shoot them and push them back ( i saw that moment when the guy is getting speed must of ppl will run away )
and the thing goes ........
Css is a Dead game there are few funny stuff which make players play this game, one of them is bhop
(if you cant do bhop and you are getting killed by Flying Zombies that's true it's not fun try to find a way to beat them and laugh at them)
There is one thing which is more powerful than your weapon
IT's Called Brain
Note: i'm not pro bhoper and i play Ze sometimes, i'm ZM player but Bhopers in ZM are annoying so much !!!