I wish Bastion was on sale at Amazon too :(.
We actually consciously mixed it up that way this week. because last week we got a lot of feedback about how people were really bummed that only one game won and they were all equally good.
We'll keep rotating games you see into the mix though 52 weeks in a year!
Maybe you guys should try making the discount proportional to the votes. Say you have a total of 80% discount. If all the votes go to one game then that gets the full 80% Off, but if the games split the votes evenly, then they all get 20% Off. It would be a pretty fun tug o war to watch.