My critics(While you're years ahead of me) are two:
1.The closes helicopter on the first work is way to bent, a bit like a sausage
2.Some of the human and humanoid characters have some positions that, to me, don't feel right. Also, some of them stands in a way that looks artificial to me(The 4 arms warrior and the "Engineers" on one of the last pictures.
But the work is very impressive, great talent. And I love the ambient you mannish on those environments.
I'm looking forward to see more and to get as good as you are.
pretty cool portfolio man. the ship one especielly haha.
one thing thou is there are some pics in there which seems like it was done before u improved maybe?
the not so cool ones like the candle skull guy and the one below it, i would suggest u keep them out of ur portfolio so people dont get mixed feelings abt it.
kinda like GPA, i find those pics kinda average down ur portfolio's "rating" alittle if that makes sense.
In terms of knowing your color theory, you're almost there. Your perspective is existent but it isn't perfect. Some pieces feels warped in perspective but it's not warped enough to let the viewer understand it is intentional and not a mistake.
One problem with your pieces is your lack of knowledge in anatomy. I understand you're heading as an environment artist but these figures in your environment ARE BRINGING DOWN your painting. Here's one that is obvious (your "bend line" is all over the place). The ideal figure has it's bend line always in the middle. If your doing proportions beyond ideal then make it consistent. I'm not even sure if your trying to do stylized (pixar like figures) or realism. This is really bad because these flaws are pulling down your pieces.
Second problem is the focal point placement. At first, it seems your incorporating rule of thirds in your composition yet the focal point are way off the mark. Read about composition theory.
I would also recommend to get in the habit of sketching a lot of scene first and making sure they are perfect before you render them. As the old saying goes, it is a colossal waste of time and effort rendering flawed drawings. Have a bunch of unfinished pieces and have a knowledgeable friend to critique them. Then render them to finish beautiful pieces. It's really unfortunate for you to waste your time on pieces that are not perfect. Get all your core fundamentals correct first. Anything after that is subjective.