First Impressions: [7/10]
at first glance what i thought (sometimes unedited thoughts
and how my mind works when i first look)
looks at poster thinks, "nice. good blending.
looks romantic/nostalgic"
looks at the description and reads,
"dark angst" thinks, "oh." now confused.
anyways, overall it left me with a good first impression.
it doesn't fall under the OMG ITS AMAZING category though.
and the first thing I noticed was that contrast would have made the
poster more vibrant and appealing. see below to what just a difference in contrast can do.

 

Technique: [17/20]
how masterful are you at blending/cutting
The blending for both characters is pretty good. no harsh edges and
yet you can distinctly tell where each character's body "ends"
I would have liked to see the tshirt / text on the right side on the boy
erased / blending / blurred out so that it would be less distracting.
also where the rose ends, i would have liked to see it transition a bit
more smoothly, it looks a bit awkward since it's close to her head.

Resources: [16/20]
does your images/stocks/brushes/textures enhance the poster
the images used are good. i like how the guy is looking away
and the girl is looking straight. i don't like how the two images
don't match color-wise. it's sort of strange to see that.
color is one way to emphasize things. so, when you have two characters
that are both main especially, either both should be in color, 
or both in black and white. 
i like the use of textures, it provides an extra dimension to the poster.
I recommend blurring the texture where it overlaps the character's faces though, 
as seen, it can make the character's face look "dirty"
the girl for example, she got some bird poop falling on her forehead.
and their skin looks bumpy/scaly
dont be afraid to edit the texture
i like that you tried to include stocks like the rose, 
but its so subtle that it might as well not be there.
if you want to add a stock make it be seen,