I am not exactly sure about the first picture... The textures don''t match (between the two moutains), the "water" is not really visible (or maybe it''s jsut the haze in the horizon ?).
And I think you were trying to make some sort of dust cloud to show they are landing ? I think it''s pretty cool, but it still kinda look messy.
My main criticism would be the lack of contrast. That is, the good old rule : warm foreground, cold background. You have it, but I don''t know, I think the dust covers it all, killing the contrast. Or maybe it''s just me

On the other hand the second picture is really cool

Maybe not really well balanced (all the weight is on the bottom and right), but definitely a good feel of depth
youpla :-P
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