If you can go longer than 18 seconds you are phenomenal. It's been said that the US Air Force uses this for fighter pilots. They are expected to go for at least 2 minutes.
Give it a try but be careful...it is addictive!!
What you have to do is click on to the red square in the centre and move it out of the way of the moving black squares and rectangles without touching the side walls. Like evading attacking aircraft.
I lasted a little over 4 seconds in about 6 tries.