Cool design. I dig the flipper. Are you cool with edits? I've clearly had way to much time on my hands of late, and I've kinda been cranking them out....

Just trying to give the 'buff' look you wanted, w/o complicating the body. My understanding of anatomy is, well... minimal, but I'll try to explain what I think I did.
The pecs in the original are too small/mishapen to be pecs. They look, like Xion said, more like boobies. In the edit, I widened and rounded them. Not perfect, by any standards, but maybe more pecish than before. I gave him a six pack, too. If he's buff, and his shirt is meant to be tight as it seems to be, I felt like the right thing to do

I like it lots. Cool palette (specially the way it's used on the shirt) + cool design, like I mentioned + unique style=sexy. Keep it up.