I got a 0 it got a bit tough after staring at it for like a minute, all the colors started running together and I started to get a headache lol. That test reminds me of an app I used to play all the time, same concept essentially
I got a 4 and my problem region was the green/turquoise colors :B After staring at them for a while they all started looking the same so I had to take frequent breaks x'D