Thanks! Watching you play the game was very instructive!
I'm sorry the controls weren't more clearly explained, a tutorial or help page is definitely on the 'to do' list once the competition is over.
The big concept I can see wasn't explained to you is that you are actually swapping colors around the image. So the process is select color A, then color B and then they will swap pixels. That's why the image keeps changing on you as you click around.
I also noticed the presentation got a little confused on first play through, with Game Over and some other text all coming on the screen at the same time, sorry about that! Definitely nice to have a video of the mishap, you can bet I will be watching that one over and over to try and figure out what happened and get that bug squashed! :)
Finally, I wanted to ask what size window you played on? I noticed the 'High Score' text came up over image at times. This won't happen if the window is larger. But it's totally possible I forgot to set the default window size large enough.