The pose you've gone with looks good and convincing to me.

To the brief of a sniper hunched, accustomed to wariness: the gun hoisted up mid-action like that seems maybe uncharacteristic, you could equally hold lowered without sticking out too much. I imagine a pretty wiry physique.

Telescopes don't seem out of place, but I know nearly nothing about guns, and bayonet on a sniper?

I'd really finalise the position of the light source and figure before adding more stuff; the figures are pretty well straight facing us while the cobbles are seen from above with no change in scale coming forward, and the lamp seems like a fair distance away, going back and in quite strongly as from below.

Oh! You reminded me of how much I liked the concept of the bushes! I sadly wont be able to use the first version you liked so much due the huge amount of unmanageable dirty pixels.
Although I will give the bushes a new attempt in general.

Not that you should necessarily, but if you really wanted to clean up dirty work you could just select the darks using a low-ish threshold + flood fill with a solid colour -> inverse selection + flood fill that also. done.

Kinda agree that the brightest colour is a little distracting used so liberally btw.

@Night Sure, loads of those are beautiful and I hadn't seen them before, so thanks for that! I'm surely not knowledgeable enough to say where those might be inaccurate but it’s an unnecessary pot-luck on top of all the stuff which won’t be useful; those are presented and archived as historically notable artworks, not reference sources.
   
And of course I don't mean to say you’re crackers if that worked for you! Don't mean to overstate. But there are some well-established artist’s guides that make sense of so much, and from what’s being worked on I don’t think full spectrum anatomy will be that helpful. 

edit:

About Grey, a rather interesting example you give to its use, but I hope you didn't misunderstand me as I wasn't referring to the organs and stuff, but to the skeleton and muscle illustrations, which might be few, but still are pretty great in my eyes.

In everyone's eyes! It's excellent stuff to refer to some specific. I think later editions have some replacements of the original drawings, and the contemporary hardly anything left, which is a shame.

Used more technically, brightness is value, as in HSB. or where was the sky’s light coming from before?

I think Joe’s talking about the orthographic sidescoller projection (no vanishing points, in pure profile) versus ’proper’ perspective which, realistically, would change as your viewpoint changed (moving around the level) and the inconsistencies between the two can sometimes sit uncomfortably. The usual alternative is to just to keep discrete layers of depth without obvious vanishing points.

In a similar vein, and while I’m warming up to talk too much: the large size of the sun is working against the sense of scale a bit; if you think about the appearance to the human eye it’s really rather small, coin-sized or so, and those massive dramatic sun/moon scenes you see in photography are achieved by zooming in from a distance to a tiny crop around the sun/moon so your sense of perspective disappears and figures etc. can look dwarfed. I actually don’t think that’s terribly apparent/important to adhere to but if you’re worried about scale/perspective it might be having some impact unbeknownst.
 
Since almost everything in-scene is was pretty bright you could pop out the (ace looking) purple dude by putting a nice dark layer behind him. I kinda like the stand as is, I assume you can interact with it though (save point or something?).

Red sky looks cool; slightly ominous/strange, probably that's desirable here.

@32 Ah, ok; I can see the posing as being less direct and dramatic as it might be.

The eye-line/pose generally was intended as a bit of a nudge and a wink; I've been trying to take things in more of a self-aware homage/light ribbing direction, there’s a lot of gently amusing stuff going on that I didn't necessarily want to turn everything up to 11, (not right away at least; there’s a couple of other large graphics for game-over and completion that might be better candidates for more wish-fulfilment type stuff). I’m really pleased that something of the idea seems to be working for you anyway.

Talking of strange boxart! Inexplicably that was (apparently) the quick and dirty separately-packaged version in the US, sci-fi chrome pterosaurs and all (most had the shareware bundle). It also boasts of the 'outstanding sound' (silence) and 'over a hundred monsters' (about 60 sprites, although some are reused for lazy powered-up versions).     

I was pleasantly surprised at the yellow/grey skin combo myself!

On the yellow-washing, yeah contrast, though you could go for an alternate color for the shadows(see below), I just don't like the gray shadows since the yellow has such high saturation.

The massive brightness/sat. of the yellow is why I went for the grey; as a temper. Increasing the coverage and pairing with the similar ochre or even the complementary actually seems to increase its potency to me? I'm quite happy with the balance now but certainly was little leery of overdoing it at first ‘cos I found in the sprites that a little too much (grey) could turn them into corpses.   

...hm, that’s quite a lot of talk and little work from me. It may take a little while but I'm thinking maybe I should sketch up the other couple of big graphics and evaluate them as a group before making decisions (and god-forbid, finishing anything). 

Oh, just saw another reply! @bbrother: yeah I was worried about mirroring them completely but they are meant as alternate gender versions of the protagonist so I did want to imply some kind of parity, I will try a dark version though.