I like the overall feel, especially the setting around the character. I think the fireflies gently glowing around him actually creates a unique kind of creepiness. My main crit is that I don't think the Giant part of this guy comes across. The grass around him seems to suggest a large, but mostly average human size. The point of view could be lower to emphasize his size as well. Looking up instead of straight on. I think he might also benefit from some slime or swamp-nastiness. He seems kinda dry for a zombie lurking in the marsh. Solid work overall though, I like the texture and color subtlety in his skin.