Well, I have to say that I do like the blood you added to the soul...thing underneath the skeleton in the background, but that's all I can find that has reserved some positive feedback.

The coloring jobs are terrible, specifically regarding the sprites, some of the worst I've seen in a long while. I know that this is your first, so I won't be so critical. Instead, I'll provide some constructive feedback, as I usually do. Though, with the untalented and absurdly overly-arrogant, it ends up being wasted.

Now, if you only have MSPaint, then you're screwed, unless you can do some heavy duty color-changing in the mediocre pallette that that program provides. blacksaibot's done this before, and it's earned him respect from the best in the industry. Try to add shading to areas where shading is needed. I have no clue as to why you even changed the colors on the sprites, as...well, it was entirely unneeded. There is a sprite with Sub-Zero in his original ice-blue garb floating around MKWarehouse, and every other sprite-containing site on the web. This was a wasted effort, and poorly executed at that. Leave the coloring alone if it doesn't need to be edited.

But yeah, anyway, there really isn't much I can say, because you made some moronic moves that turned out horribly. Try shading, hightlighting, and all that.