Right. So keep in mind I'm no expert at pixel art--not by a LONG shot--and take my advice with a grain of salt. Two grains of salt. Hell, you might be better off taking the entire saltshaker. In other words, keep a good sense of skepticism about you, because for all I know I could be talking bullshit and not even realize it.
One of the things I try to avoid with pixel art is, what boils down to..."putting a flat box in space", really. Despite the fact that we're working with a 2d medium, and the fact that we're looking top-down, the object still has to look like it has 3 dimensions--which is incredibly hard, seeing as how we're looking top-down and the z-axis doesn't carry over so well. Spaceships aren't just flat pieces of paper, they have depth and things above and below them, and they need to show that.
Granted, that's a little hard to do without shading, but...
Another thing I try to avoid is making my ship out of very basic shapes. One of the things I noticed about the screencap of the Kodiak versus your drawing is that a
lot of the slanted features like the raised area towards the back and some of the engine-block-things which slope forwards at the front of the ship, aren't really present on your artwork; instead yours kinda looks like a box with other boxes next to it. (That's not to say you should avoid basic shapes entirely--TaxiService's
Crimson Lady/Ol' Triggernaut are a big polygon, but they're still visually interesting with lots of detail, and still look like they have depth/the z-axis on them. I'm just not skilled enough to pull that off, to be frank.)
I drew up a quick sketch to try and show more of the slanting on the ship. Crappy sketch on crappy paper with crappy scan quality, but hopefully it illustrates my point--perhaps it's the fact that it's sketchy (and sketches are more pleasing to the eye than clean lineart because
science), but I think it looks more visually interesting and shows some of the less basic shapes of the Kodiak's hull.
There's some highlighter marks on the sketch which correspond to parts of the Kodiak. I want to discuss these in more detail:
The green highlighter marks are to compare the length of the main body and the length of the "neck", excluding the head at the front. They're about equal. When I first looked at your ship, I thought your neck was too long--but now that I look at your ship art, yours also follows this rule. As I was sketching I wondered why your art looked a bit off--I realized it was because the side engines didn't extend as far as the neck, leaving this extremely bulky body with one rather slender neck sticking out of it a bit awkwardly.
The orange and the pink on the sketch correspond to sloped bits on the Kodiak. The pink bits extend halfway up the neck of the Kodiak, and the orange forms the forward part of the main body.
The way the orange bit is drawn in the sketch, it may look like the ship is narrowing towards the neck. I've tried to avoid this with two things:
1) proper shading (okay this one isn't actually implemented yet)
2) The placement of the neck-to-body connection. Notice how the neck comes up part of the way past the bottom of the orange slope, but not at the top of the slope.
I also tried to sketch the sloped surfaces on top of the main body, as you can see in the upper-right-hand corner of the sketch. But those didn't turn out so good. I admit, they're pretty hard to do.
Now, to the engine nacelles. I drew the cylindrical rotation axis of the engines all the way through the ship just to get an idea of where things were. I extended the outer engines out further, and also tried to show that the front end of the engine nacelle is narrower than the back end. The engine ends face downwards, so probably won't be visible from the top-down view. Also, note that the back end of the inner engines fuse with the main body, whereas the front end narrows down to look like a separate body.
The parts outlined in blue are all part of the same horizontal plane, and have no division between them. Whereas yours seem to be completely separated by a pixel-thin line, which makes it seem like the entire inner engine is separate from the main body but somehow still connected.
The bottom-right corner of the sketch is me trying to show a detail of the engine. Feel free to disregard it, if you want.
Some other things to note.
The main body is rather slender compared to the neck--so I widened the body in my sketch, and it's about 2x as wide as the neck is. If you do decide to follow my advice, keep in mind the size of the hangar--as it is, your ship art is already looking a bit big for the hangar. You may have to shrink parts of your ship down, rather than stretching them out.
I usually try to avoid sharp corners on the outer edges of my pixel art. Sharp corners make things look unnaturally precise, IMO. Here's a quick look:
The one on the left is unedited. The one on the right, I added a bit of "rounding" to the corner.
I see you've been adding random patchwork colors all over the body. I assume this is for visual interest, since flat colors on a flat shape look really boring. Don't worry about adding patches, unless your Kodiak actually does have patches all over it. Adding depth to the image and giving it proper shading should give it plenty of visual interest--and if that's not enough, you can add a patch here and there, or a greeble (mechanical bit) too. Again with a TaxiService ship, but take a look at
The Hooker for examples of plating, shading, and greebling on a flat surface.
The top fins of the Kodiak are a lot wider than you've drawn them to be. When I first saw them, I thought they were propellers! Instead of a long thin shape, they should be more squarish.
So there's my opinion of your ship art. But again, I'm not an artist by trade, and I've barely had a year's experience with pixel art anyway. Feel free to tell me if you disagree, or if I'm just flat-out wrong in some places.