I like the muted palette too!
I think it's pretty good, just needs some cleaning up. As far as the contrast issues on the characters, you might want to try more saturation or just a hue shift towards the warmest colors (opposite with the environment). As far as the poses go, they feel pretty solid, but the dwarf and skeleton seem to lean a bit.
I like the texture of the golem but I'd use a bit different forms for him - I think he'd look more interesting and intimidating, if the chest/pelvis area was more humanoid like:
Sand tiles - are they supposed to be sand? I like their texture, but they feel more like a firm, pretty solid dirt, or maybe dried, hardened mud (well, except the color, of course:P). Depends what you want, for sand I'd use a more dune-like, stylized texture.
Not sure how WIP is the slime, but the current texture is very inappropriate IMO - colors and the bit of dither suggest something more like sand - unless that's something you want, but the idea of the slime is very established and a sandy slime might not look right to your "audience"
. There was a thread about a slime sprite not while ago, and I'll repost Cyangmou's image, since it's very helpful in this matter
(hope you don't mind)
