Gamesprites and background need improvement

[9_6]

Hello community,
I've recently started to make a little game involving a giant worm eating stuff.
The enemys should be futuristic ships (not space) which have a somewhat dirty and used look so nothing shiny and new.
Here's what I have so far:



I don't think I acheived the dirty and used look.
Everything still looks clean and new although I used 'dirty' colours like red and green to make stuff rusty but it's simply not gonna happen.
I would apreciate some pointers on how to improve it.

The house doesn't look too interesting either but I have absolutely no idea what to do about it :(
I already used a reference for it and spent way too long on getting it where it is now but i'm not pleased with what I see.
I'm not that much of an experienced background drawer, actually drawing a background is miles out of my comfort zone.
I don't like it but I want to get it done now. I can't seem to get it done myself propperly though so I need the help of someone who knows how to do things right.
Yes I mean you :)

If you want to see what the game is supposed to be like, here's a techdemo:
Link
controls: move the mouse to move around, let click to spout ink, right click to open/ close your mouth.

[candiru]

Nice game. Is there a goal, except to stay alive? For the ships to look older, maybe changing the palette will help. This one has softer highlights, less contrast..

[Hishnak]

Hmmm...I actually prefer the original myself. Currently everything is a little bit smooth and paneled, like these ships just came out of the factory. Add some more detail, wires, grates, fans, pistons, tubes and other stuff that give it the "I've just been through 100 years of battle in another dimension".

Also, you could switch up the palate between ships. Having them all that same drab grey/green may get old after awhile. You could also put some bands of color like painted metal on them then scratch up the paint a bit to give it the rugged feel.

[Turbo]

While i think the original has more readibility, due to strong highlights and contrast, it is true that old metal gets dull and loses that chrome effect, as rust takes over, getting a similar effect to candiru's edit.

From these sprites, i think the first chopper is the one that reads the best, due to good contrast, the others are too dark.

Try having several hues on the metal, to show some variance in texture. If you add many hues and manage to make them bind well with each other, i think you'll achieve a worn, muddy look.