I wanna help, so I'll give you my thoughts on all the parts:
Cursebolt - Not very good, sorry. It's pretty empty and relies too much on the background. Block choice isn't good either :/
Haastregt - It's alright I guess, but I don't like how the blocks are detached on the wave parts.
Fruitsnack - I really like the gameplay. Design isn't bad either.
Grandtouring3 - Same problem with Cursebolt's part, too empty without the custom background.
MM2x2 - Blending ;__;
Fluffy - I like the 1.9 style, but needs more deco.
Flashmick72 - KreygasmTimelink - Way too much blue, to the point where you can barely tell the decorations apart from the background.
GDLev - Very unique, but it doesn't fit the rest of the level.
Rexone - The moving objects stand out too much from everything else.
Yasarov - I really like the design style. Reminds me of Takeoff in a way.
Lax - The ship part is nice, but the cube has way too much copypaste.
WillFlame - Feels very rushed :L
Overall, I'd say Flashmick's part is the best