Original
Quit eoriginal concept art for these.
I'd say it all seems a bit rushed and not very planned, though. The monsters look real good and original, which is good, I like how some seem like hybrids between creatures we know of. The top right looks very odd, the lighting I'm not too sure of, and the background is quite abstract, I'm not sure what's going on there.
The background on the bottom two looks really cool
Looks a bit like a sketch at times, some lines that could be removed. The shading is pretty well done on all of them apart from the top right one.