I think it can be brighter even a bit more, but I'm aware we have dark maps like this on CC, so it's not necesarry. It's just my opinion, because I don't particularly like those maps as well.
As for the gameplay, I look forward to the progress you're making, because it's obvious you're putting some serious work into it. I'll comment on that later.
It's a good first draft! Keep the good work going.