I think you did a very good job on it. Definitely a peice I'm more fond of on newgrounds.
I don't think it would be the same without the dust spread around. It gives it character, as well as the lighting.
One thing I really like is lineart, that isn't an error so much as preference, you won me over on that.
Textures can always be improved don't be hard on yourself about that.
The only thing I'd agree with is that it could be darker. I like the fading around the corners but I do think if it was just made darker it might improve the picture overall, none the less you did good on this. We're on newgrounds afterall, no need to dedicate hours to making the 'perfect' picture.
Good job and keep it up, hopefully you'll release more work like such!
(Keep the shiney metal!)