Hey ben. This is looking awesome man. Amazing concept and composition. Though, I think there are a few things that could be done to make this even better.
Here's an edit to demonstrate what I mean ( Mine <---> yours)
Colors:
Here is where I think you're lacking the most (mostly in the flying machine, but other areas of your works as well). You've got the nice brown and gritty steampunk flow going on, but some hue shifts you are using are just bizzar and its breaking the image a bit.
Take a look at the wood part of your flying machine for a second. You've got a nice warm brown that starts to hue shift towards purple as it gets darker - then *BAM* it shifts back up to a muddy brown again destroying a lot of potential depth. I suggest continuing the shift in to the desaturated purples to finish the flow of that ramp.
This same thing also occurs on your wings. You start to shift to purple, then back to muddy-ugly-brown for the darkest shade. I also suggest shifting that towards purple. If you're smart with this, you can offset the two new colors enough for them to act as buffers for eachother. My image demonstrates this which also gives the appearance of more colors with none added. (see areas such as the shading under the wings)
The red on top of the wings is also slightly obnoxious to the image. I toned it down a bit. Not too big of a change, but it helped the ramp tremendously. I also took out the second lightest color on the wings... it just didn't seem like it was doing much. I then tweaked the other to fill the void.
Consistency and technicalities:
some areas of your image I like a lot, and others not so much. this is most likely due to the inconsistent rendering. On parts it seems like you're going for the whole '1px colored outline / fejer-esque' look, and others you evade the outline entirely. This breaks the image a bit. Based on your character sprite, I'm going to assume you were going for the outline look, and applied that to the rest of the image. While doing this I tweaked a lot of colors slightly. Some where too close, some too contrasted. You want your palette to be the most versatile as possible obviously, and these are things you should always keep in mind
the last thing that could be fixed up a bit is your lines in general. You're using not so pixel-friendly curves and such in there. Its amazing how much little curve adjustments can improve a pixel image. I also touched up some messy AA.
Anyway, thats all i've got. Again, I absolutely love this whole concept. I'm excited to see where this goes.
-Dan
