Here's an excellent YouTube video of Boxhead 2play Rooms.... 'HeadBox' created this video on YouTube on how to kill as many zombies as possible by building two walls.... 

It's awesome... I love the strategy he's using and the floor that has turned red completely! Nice one..... Don't forget to send in more of these fantastic vids to me (seantcooper) on YouTube please. We can't get enough of them.