Um.

Well, you know what? If you can teach me to cast necromantic spells through pixelart rituals, I'd be all for that. What do I need to do to raise the dead with photoshop?

Have you considered shading or detailing beyond (admittedly pretty clean) blocks of solid color?

Once more, into the breach!

My preferences:
Giant mechas. Gundam-ish super robot designs are fine, as are more realistic industrial-looking machines of war.
Knights! Detailed, shiny plate armor, preferably more fantastic and less realistic. (No boobplate though please. Female armor ought to be as decent as a male's armor would be.)
Pokemon-like 'upgrade paths' for a character design.
Fantastic landscapes- scifi or fantasy.
Interesting skyscapes at any time of day. Midday, sunset, starscapes at night, whatever.
Portraits/full-body sprites.
Organic designs- no cubism plz
Painterly techniques, with a focus on cluster technique, rather than fill-in-the-lineart works.
Videogame mockups, with a slight preference for top-down tactical stuff.

Above all else, I want to see pieces of art which would stand on their own merits, rather than attempting to smash every single thing I listed above into a single picture for the lolz. Make something that you would think is cool!

Eh, the coloration's fine, if the intended mood is a dreary, dead forest with little life. Given the title is about curses, I think it's fitting.

As for the cliffs, you don't have to stick to the super-geometrized forms! Take a look at some RPG tilesets for ideas. I'd link some, but I don't know where to find them offhand.

You might even consider something like this- a simple two-tone organic tileset which works by overlapping tiles to imply form by using the tiles themselves as macro-scale pixels.

I find that telling new pixelartists 'make it shiny' is an easier inferential step than 'raise the contrast'. Most new artists don't have a good heuristic of how much contrast is enough and when you tell them to raise the contrast they just raise it a little bit and you have to keep pushing them. At the least, making things shiny immediately conveys the message 'you need really, really, really bright spots'.