I loved these in Games Magazine (doing them with paper and pencil). The online implementation is good. Like somebody else mentioned, a Next Level button would be nice. Some basic tips for new players: Click all the 1s first, since they are just themselves. Do the 2s next, because they will always be right next to each other. Once you start getting the smaller numbers filled in the paths for the higher numbers will become obvious.
I generally don't have a lot of patience for games like this, but this was a lot of fun. Maybe it was the music. I played until 999 but after 100 tries I had to stop. Great game though.
I liked it a lot. The ambience was good. My only complaint is the items hidden in areas you wouldn't think to click. Like the green key...not logical and I had to find a spoiler for it. Makes it less fun when you have to randomly click every pixel to hope to find something.
 "Color Link-a-Pix Light Vol 1"){kind=icon}
 "Lolwut, The Game"){kind=icon}
 "Monster Basement"){kind=icon}
 "Vector Runner"){kind=icon}