(adsbygoogle = window.adsbygoogle || []).push({});
Right, I found a way to keep repairing the windows without gettin' attacked.
I don't know, if this gives you points, but you can keep healing the window hundreds of times
1) Get to about round 4.
2) Make sure there's one zombie left and he's outside the window.
3) Throw a grenade so it blows of his legs.
4) He will now be on the floor, and he will keep ripping of the wood.
5) You won't get hit, and you can just keep repairing.
As I said, I don't know if you get points of it. You should do

Don't kill him or it will go to the next round and you'll have to do it over again.