Really nice man!

You seem to like metroid alot.. would you like to help make some sprites for a fangame project named Metroid Prime 2d? it is a highly popular fangame that's been around for years and years. PM for more info if you're interesed! but it's just for fun, no pay. :)

Hehe, no, I don't plan on remaking it myself, I have no programing/coding skills. This was just a little dedication thing.

And I think I see what you mean about the foreground tiles, the darkest color looks too bright against the dark background thanks to the yellow hue, right? And any tips on what hue/color scheme I could give the background? I've tried a blue tint, a brown tint, and a black tint, and the Queen blends into all of them. Perhaps something reddish? And thanks for you're comments, they're helping me a lot!

Whoa! Nice! Are you serious about remaking Metroid 2? Are you, are you?
I do agree that the foreground tiles are kinda ugly, and the saturation difference between the foreground monster and the BG rocks isn't enough to make it stand out.
Also, you know, the reason the queen metroid didn't move much on GB was because she was a part of the tile background, and just couldn't animate. On GBA you can make this fight much more interesting: )

Sprites look good (if a bit rought on the monster) but really not keen on the background, or the tiles at all.  The tiles coloring (the browns) looks really odd.  Like they've been surrounded in a color far too light.

Executed perfectly, nice job. 

Samus is great. The rest too... Only one thing that I don't like: the rocks (those braun, down)

Very, very nice :)