Depression

This is amazing. For a quick job (10 minutes) the level of detail and balance is fantastic. The mood is evocative and dark. Eerie is a good word for it as well. It immediately reminded me of Theodor Kittelsen, who is one of my favorite artists. I haven't played Limbo but I've heard of it, and checked some pictures before writing this critique, and it is definitely inspired by.

One minor composition point: The branch near the birds beak is a little distracting. While life shots tend to have these issues, in an illustration there is a little more leeway. I might have cleaned that up a bit and put some distance between the beak and the branch.

Other than that I would give this a flawless execution, especially considering the time it took. Fantastic work.