Interesting options. The yellow makes it stand out against the purple background. The red eyes make it almost humourous as it looks like the troll face is extremely high. At first glance I wanted to laugh. I can still see the white outline. I suppose it's been coloured in with paint. Perhaps some definition with different tones on yellow could have been used to extenuate the tones of the face. Although the way it is now give it a pop art kind of feel as if it were a slogan or something of the sort. I'd like to have known more on what the artist wanted to portray with it. But that said I still like it.