The green stuff was just vegetation noise, it'd be better to use actual plants but I think some mould here and there wouldn't hurt.
Whether the brown tech tiles are too dark or not probably depends on your monitor - I was just making it look like the tile had been pulled out and the dirt below it exposed.
Craters would simply be added wherever an explosion took place - you could just read whether the tile was dirt or tech and put the appropriate crater there.
Glad you like the edit.
With a command based interface make sure you've got a good tutorial. I know it seems like an odd thing to focus on now but you'll need to explain the interface well. I think a small, handmade "training mission" would be nice.
The gameplay as a whole sounds pretty good, an endless world is a bit.. un-fun though. I know losing is fun and all that but it'd be nice to see a randomly generated 16x16 wasteland that two players could have a war on, fighting for relics and land; some sort of epic scale chess.
This is the kind of game that would be awesome if you could play by relay - a daily move, "Dragoon Lance to F6, Chicken Mecha 31 to E12" kind of deal. If you happen to be online at the same time as your opponent you could play a whole war in 30 minutes, but you could also spend days playing out a small skirmish. Turn based games can be played at any speed, which is a wonderful thing. Have a think about it on your week off.
I'd love to see how you envisage the overworld, especially with many "clans" of robots around.
Looking forward to more, I'll be sure to give some more criticism on the arrival of new art or gameplay ideas