These are looking pretty good, though the second one I'd make the edges of mud/sand smoother, right now it's giving off more of a rock vibe with it's jagged edges.
Finally got out of bed, here are the correct images. Tidied up the edges and loops. The wheels still have the symmetry loop and there are a few edges that got cut in in the export.
Try to get rid of that supersharp edges on the buildings by either bevel/chamfer it a little bit or break it up with some crack or edge decal. Keep up the good work!
pretty good, the edges of the bricks look a smashed up a bit too uniformly, it seems like some of them should have pretty good clean edges here and there.
i think your edges are too tightly beveled in the high poly.. correspondingly, there's little smooth edge shading on your low poly.. try making them softer :)
I would recommend tightening a lot of your edges during the retopo. There are a few pinched corners and soft panel line edges for a mechanical space ship. This is a good starting point though!