moonlit city:
I agree with jams that this much harder to read, took a while before i got what I was actually looking at. This might be because most of the bg is just the stripped floor, where the eye gets lost and doesn't remember the perspective. The two enemies are also very confusing and seem to defy the perspective, I don't get the at all. Nice antagonist and player with giant claws =).

The bright yellow tiles may be muddying the readability of the floor. Perhaps if the pattern was more muted or changed altogether, then it wouldn't clash so much with the active objects on-screen. I'm going to go recheck these images in gray-scale format to be sure. The two enemies are simply exaggerated laser attacks, and I'll probably change their design as well - I wanted the knight's attacks to have a skull theme, but it has to read well and not feel 'off' in terms of perspective. A nice combination of normal and paranormal attacks is in order.

Is the city background behind the knight alright or does the juxtaposition hurt the image? I think the knight himself might need a bright palette. I should probably edit the brick wall he's standing on as well - looking at it again it seems to resemble a cake full of Smarties.

abandoned warehouse:
Really nice bg, cool concrete render. Awesome explosions! I wish I could do explosions like that! Player looks good but need color for readability. Antagonist has really wierd anatomy - are the giant boobs intended?

The player here is supposed to be the white/gray-themed character of the cast, and I liked the idea of a character clad all in white - it seemed stylish at the time - but I'll experiment with colour combinations to see if they play off the levels better, perhaps trying out a snappy dark grey suit. As a (botched) experimented-upon person the boss here has a deformed body - exaggerated limbs and torso to contrast with her normal-sized head - visually emphasizing the mutation. The boobs are intentional.

sea bridge:
Good colors, good bg. Is the yellow thing the player? I'm also having issues with having shadow on both sides of the lower bridge. Should be only 1 px wide on one side I think.

The yellow thing is my attempt at drawing a car - DeLorean to be exact - for the blonde of the group. It could probably do with being redrawn to resemble a more generic model (with actual windows and sunroof). Good eye on the bridge also, I'll fix that.