The VG Resource

I've been messing around with these for a little bit and I thought I'd post them. They're five different tanks from five different armies, starting from top down its: the Rojaan (Row-hey-an) Army, Verdean Army, Azurilian Army, the Grisanian Army and the Amarillian Army. I have animations for all of them but I didn't want to post them all so just the Rojaan ones will suffice for now. I also have created quite a few background objects so I made a little picture to show off some of them. I have a backstory and some really tiny soldiers but, once again, I don't want to post them right now. As of now, I really don't know what to do with them so... yeah. Hope you enjoy!

I think your red tank and blue tank need a bit more contrast.
The grey tank and the green tank seem to have a bit of banding, but I'm not sure if that's always a bad thing.
I can't crit the animation, since it's not animated.
Otherwise, though, I think they look pretty good. The BG you did is pretty nice, too; the trees on the right side look unfinished, but everything else there is pretty nice.

I really like how the yellow one looks like it's converted farm equipment.

I really don't like your colour choice for the red tank. I also think you could benefit from not using pure black outlines inside the sprites

cant agree more with the green ghost. for sprites of that size, the use of black lines does nothing but "eat" the details away, specially with those lowe contrast gradient ramps you got there.