I get 0 points if I have it wrong. Is this is a bug or is that just how the algorithm works? It would be better to have a maximum score for each round and then basing the score depending on your browser size compared to the target.
That's actually really clever, I love it, especially the colour changing. It might be a good idea to display a hint to resize the browser to the displayed resolution on the first play, since Hackers tend not to read instructions.