DarthBo said:

The shadow of the snowspeeder makes no sense either btw.
It's in front of the walker, yet its shadow is behind it. The tow cable's shadow is wrong as well. (it's more evident if you watch it in motion)

Not sure if you can fix it though, but you've surprised me before ^^

If the sunlight is coming from a 45% angle, the shadow would make sense. Regardless, I would add the snowy feet to the subsequent AT-AT shots within this sequence.

In regards to the "Luke scratching the AT-AT's belly" scene, maybe you could take some of the 1080p AT-AT leg shots and mask them onto the leg gear on the lower left below Luke. The 1080p shots should be more open to enlargement for such things (with maybe a dash of extra FX - details, shadows, etc - on the leg gears to seal the deal).

I take it this is the offending element? If anything, it seems all it needs is the outer ring you see on the model leg (the ring above is flat and smooth, whereas below the inner ring is inset). Also, going by the picture below, shouldn't there be another inner leg joint on the lower left in the pic above (of course, it would cover up Luke's lightsaber arm and the door, which is maybe why the shot is so off - there's a missing leg!)?

Never noticed the AT-ATs bowel problems, but it looks like it needs some serious proctology there (not that it matters, being that it just got blown apart). Still, does the tube need to be connected to what looks like a rear door?