A fully upgraded wall seems to be very effective. It'll kill off a few zombies before it falls. Also, if you hear a scream, don't let the white enemy on the mini-map hit the barrier. You can't repair it after.
Anyway, I love games where physics are involved. This game takes some quick thinking to stay alive. So for the physics and the challenge and the very well made game...5/5
Why are most people in the world so judgemental? Even so, when judging, having double standards tarnishes the score. So for what this game intends, it serves. 5/5 Perfect for afk moments.
I don't know how many times it's been said, but it is NOT based upon luck. It takes skill to know when to stop, so most of the time your Zilches are your own fault. Learn what to take and when before you judge this game and think it's rigged, it's not. Here's proof...again...http://blog.playr.co.uk/2008/11/zilch-about-cpu-players.html