That concept art is pretty rough looking so hard to say but that "hand painted" feel could possibly work out.

Braid had an interesting art style and it worked out pretty well.

is there going to be more art to your levels or is it just going to be what you have shown? I'm hoping there will be more hehe (:

Edit:

BTW, the maker of Braid said he had the game working 100% with programmer art and then after the fact had someone pretty it up and it turned out great, so maybe thatd be an option for you.

Something else though, if you have multiple layers of art that looks like that, and do paralax scrolling (ie faking stuff in the distance etc) and really put some effort into that art style you are showing, it could work out and be neat lookin

Your art is nice looking

from the concept art it was hard to tell if you knew what you were doing artistically or not, but i can see that you obviously do now

the concept art looks rough-ish like i said but i might not be seeing your vision 100%

Rules are made to be broken so maybe you are onto something really neat.

I'd be interested in seeing what you come up with based on the high quality of your "regular" art (:

Now I don't mean to be dismissive because I very much support exploration of new aesthetics, but your concepts look to be simple variations on use of a white paint/airbrush with the spacing setting altered and a bit of playing around with the smudge tool. What I see looks to be the first steps of someone exploring the art tools at their disposal, looking at what products the tools make through unsophisticated use rather than using the tools as a means to facilitate a higher-level expression (higher level in terms of expressing a concept rather than expressing the materiality of the tools/media themselves, in the sense that Modern painting values, for you Fine Art nerds out there).
Heh, it really reminds me of stuff I made with Photoshop back 10 years ago when I was first learning the tools with my shiny new clunky Wacom tablet.

It seems you're new to digital art -- via Gimp? -- and I quite appreciate that you make an effort to write clearly about your intentions, but I think whatever you are proposing would be more clearly and emphatically expressed if you had more practice, more technique to pull from to express whatever your ideas are.

In short I say: draw, practice, learn technique. If you have a good idea in there, put in the effort and make the long-term investment required to express it through means that will do it justice.