Annoying
I think the idea was good, but I found it annoying to play to be honest. The green block kept changing it´s direction all the time and when I finally got my mouse on it the red block was very close so I had to move it off and go chasing the green one again. This all kinda pissed me off. I know the game wouldn´t be very challenging if the blocks kept going in straight lines, but you could make them move a bit slower and make them have some moving-pattern that they´ll follow for a while. Not the complete randomness it was now.
Also I missed the replay button and right click => rewind didn´t take me to the beginning either. Please add some kinda button that starts the game over again, it´s not that hard to make.
Overall 4 out of 10, 2 out of 5. I didn´t like it much. I suggest you try to develop the game a bit more. Perhaps add a few power-ups or something (+ points? slower blocks? no effects from red block?). Also work on a better lay-out.
~Auz, Review Request Club