Yea, I was pretty upset when I saw the bug as it was after the deadline. Luckily, you can still progress if you have a trap hitting the entrance (the villagers will also start to die after 40 seconds). You can also set the number of villagers to be lower before starting, if you can beat them all before the 3rd level you will be able to avoid the glitch.
Thanks for the feedback! Obviously it was a very important chicken ;)