I have to agree with st0ven about the different elements in the mock up not matching stylistically.  Mainly because of the "heavy inking" on the sprites, yet the softness of the background.  Aso the cripness and sharpness of the sprites with the relitivly fuzziness of the background.  And while it could just be cause I dont know what the games actually like, but there seems to be alot of unused space in the screen.  The trees also just seem to big too me, compared to the sprites.  I mean I guess they could be very large pines but something about them makes me see them more as smaller pine trees, and the fact that theyre in the distance makes me feel they should be a bit smaller.  It could be because of the way the trees bend and tip over a bit.  I think taller trees tend to be more straight, as a very tall pine bending like that might tip over (? or the trunk is thicker so the weight of the snow/leaves doesnt bend the trunk), and the pines/leaves start higher off the ground, but then again Im not a tree expert in the least.  I like the yeti though.

ok I see what you mean.  I still think the pose looks wierd on the guy though, looks fine on the female though I guess.

edit: ok update

I should clarify the left frame is supposed to be the female template and the right the male.  With the male I tried to make the pose a little less stiff by having one leg slightly in front of the other and one arm slightly more foreward but I but think it worked due to the size.

sorry my cretique isnt on anything you asked for cretique on, but I did a quick edit

I think it would look better if you gave the rocks some depth like I did by showing the side or something, but you would have to just do it alot better than it is in my edit.  And the water was just something I thought would make it look better but maybe thats not what youre going for, but I felt it added a bit of depth to the picture.  Also I think its wierd how the clouds go up to follow the shape of the mountain.
The rocks could be improved though, maybe you could add more contrast by making the darkest color inside the rocks (not the dark color connecting the rocks) a little darker.  Maybe you could add some more geometric lines inside the rocks.  Sorry I guess its sort of hard to explain how to improve it though.

Im starting to work on a new platform game, which I want to give an nes look to.  Im using the nes palette.  So basically I want to get the standing sprite good before I animate it.  Heres the first versions:

heres the new versions:

it has 5 colors, which is the amount of colors I want to stick with.  Any comments at crits welcome.