I undercoated it black, and did a couple of coats of dark green and a wash before two successively lighter green drybrushes. I painted the metal and smeared on a lot of Typhus Corrosion. I think maybe it could have done with a revisit of the lightest drybrush?
I then added a bunch of tufts by Gamers Grass that I picked up from Bad Squiddo. The idea was to make it look out of commission with plantlife growing out of it. I think it mostly worked, but I think the blue one in the middle is probably a little too big.
There's lots of fun details you could take time to pick out if you fancied it, but I went with a very simply paint scheme for tabletop gaming quality.