Right, well this is interesting.
Well, first and foremost, let's talk proportions (lol).
I think the only proportion problem (at least that I can see), are his arms and shoulders. His left arm looks a bit shoved out from his body, like he has an extended shoulder, and the other arm, looks like it's a bit close to his body, lol.
Almost like you got the balance wrong .
Also, his head looks a little flattened, but still.

Anyhow though, I like how you adding elements to make him look more like a ninja, while also adding other elements that make him more like a machine.
They all fit in well with his design, though I would be wary that if he were to be put in the games like that, it may be a little "busy".

As for the pose, which is no doubt the MK3 pose, I would've liked to see something a bit more original, instead of just standing there, like a fighting stance. This does do fine though .

Anyhow, good job .

Well this is awsome.
Even though it's just his MK3 pose redrawn with extra props, he still looks damn delicious.
I love it.

This is the MK3 pose, but its not a direct copy of it so I'm sure there will be no one who will say otherwise. As with your previous works, I do like this much. But, about the right shoulder, it should be out more. If you look at the way his feet are positioned, you should be able to better see the right shoulder. At the angle you have it, it would seem Sektor was standing at sort of an angle, when really he's just standing straight-forward basically. But as in the past, you are strong in details. To me, it looks like you readjusted the head somewhat, which is a nice idea, just making a palette swap of the basic 'cyborg' wouldn't be great really, but the way you changed it was good, I like it. Though, the 'neck' looks a but long to me.

The body is flawless, I love the details. The hoses on his left arm are wonderfully done. I must say he looks a but more 'bulky' than his MK3 design, which is nice because given your story one would think that an upgrade would make him more powerful. Given that his right arm is at that 'tilt' I am guessing you can't see his fist as you can in the on the left arm. It looks like the underside of the right arm to me, that does seem a bit odd. We should be able to see the side of his arm I think, if the proportions were correct. Still, that's really the only problem I see with this. The 'belt' is great, very 'ninja' like I guess, as with your Smoke design I like the patterns you used.

Legs are well done, they seem to match the position they appear to be in. The knees don't look too thin, as alot of times they are drawn, so good work there. Another nice concept, I like this look.

I like the idea of Sektor becoming a more efficient killer. The story writes itself if he starts souping up his arsenal and body. Good job!

Thanks a lot for all your replies. I admit I used the standard MK3 Pose for this but since I was working on a new look I didn't think people would mind it that much. If I have some time I'll try to draw him in some other pose.

As for the proportions in his shoulders and arms, I can see where you guys are having problems with it. Problem is I don't quite see all those things unless they're pointed out to me.

Anyway thanks a lot, and by the way, if anyone wants to color my smoke or sektor concept, you're free to do so. I'd like to see what they'd look like in colour but since I have absolutely no idea how to do that, I'm not going to try myself.