Needing help to make my vidya game levels better looking

[Greatdictator]

So ive been on this forum for a while and been wanting to use this section for a while too...just never really drummed up the courage to do so .
But seeing how its for something important i figured i might as well .
So im working on makeing levels for me and my friends game so that we can show it off at a game dev conference in my country, to which we will be going in around a month or two .So i could use your help in figureing out whats missing from the levels or how to get certian effects to look better for the enviroments.
So now to some info on the game , the game is ment to be in the style of Dexters Lab with the main protagonists being a robot and a small blob . Its primarily a 2D puzzle platform game in the sense of the lost vikings from good ol Blizzard.

Anyways heres the content :I


And heres a link to the LARGER version
http://imgur.com/c1wcY5k

And heres some reffrence stuff for Dexters lab.
http://hdwallpapers.cat/wallpaper/dexter...-23531.jpg
https://c2.staticflickr.com/4/3051/27023...3fcc06.jpg
http://www.blujay.com/1/525/3706518_s1_i3.jpg

Thanks in advance