I do remember this game, though I never actually played it.
Your sprite is too dark. It will be lost on any dark background ( like a space background ). It also looks very flat and a lot of the anatomy is difficult to read ( the feet for example ).
You seem to gradient everything. This increases the flat look. Look at the pillars. They go from dark grey-ish yellow to bright yellow straight across. It just doesn't look realistic.
I also don't understand why you mirrored the pillars. Unless there is some hidden light source coming from the center there is no reason to do this and it will look bad when there are more then 2 of them.
The colors you chose for the background is very uninteresting. Bright saturated yellow to greenish grey? Even though I don't think the original game was very good color-wise, if you look at their bricks, you find desaturated bright yellow, orange, copper, brown, dark redish-brown, and dark desaturated blue.
You realize its difficult for someone to distinguish from a pixel representing detail and a pixel added for dithering? To me the stones look grainy. That's what happens when you over-detail a piece. You need to ease off a bit and allow the user to see more with less, and only add detail where it will be effective. All those tiny pixels everywhere just overwhelm the eye.
On a more positive not, your work here is pretty good. Just a bit flat looking, and maybe a bit over-detailed.