Noice stuff here but it all feels so 'unfinished' to me. Like, "hey dude nice roughs can you render them out, now?"
There's a lot of details on yours that I really like, such as those pink reflections across the eye, the 5 pixels of dark gray border between the pink and gray segments on the beak, or even things as minor as that single gray pixel at the bottom of his iris. These details work visually, but I can't figure out their justification enough to feel confident I could add them myself.
sounds like you're thinking hard about how to do things 'right', which is kind of missing the point and will just confuse and bewilder. Because of course there is no Way To Do Things. I dunno about inane but beyond basic things like "this area needs more contrast" and "that thing doesn't stand out enough" or "what the hell is that and why did I put it there let me get rid of it oh damn now I remember why I put it there shit shit shit," the only real explanation I can ever offer for details like that is 'because it looked good?'
I think it looks a little better if I put this pixel here and move this one over and this area needs a little something so I'll put a stripe on that part oh damn that's too dark let me lighten that up, there. It's just a matter of getting an eye for these kinds of things, I think?
And then of course there's the matter of more technical issues like how to properly use AA and avoiding pillow-shading and tangents and banding and when and where to use dithering etc. but that's all stuff that's kind of like 'you gotta do it', you know? And the more you do it the more you'll understand how it's done, dig?
As for yer work actual, I think your color ramps are too straight. Blue things are blue everywhere, and red is red all around, and saturated saturated, even in shadow, even in light. Love the bird guy. You might want to look at some refs for how spiders walk. Neon zombie is leanin' leanin' back as he goes. I made an edit of various things in several places.
Not fond of the healthbar. I think I just don't like tapered healthbars. They've always bugged me. Increased contrast and detail on character and gems. AA'd a bit. Wasn't sure if he was a rat or a dog, assumed dog because of meat collectibles?
Don't think there's anything wrong with using large areas of flat color in bgs - it works especially well on the trees in your mockup, I think - but it might work better on the foreground if you stopped to consider the form of the rock and makeup of the ground, locate a consistent lightsource and figure out how it hits the surfaces. I think flat shading like that tends to work best when objects are considered as planes rather than curves, so you might want to think of more geometrical formations in your environments than organic ones; perhaps the ground is made up of cubes of varying size and angle?
I hope that makes sense and is also helpful, or if not one then the other