It's looks like a lot of effort went into the wall. I think for me personally the skin tone is a little off, and that should be a relatively easy thing to change. A bit pinker - a more healthy glow - would work better, I feel. The colour in the original scan is richer.

As a more complex thing, I personally find the snowman close to us a bit too 'fluffy'. The soft blue for the outlines and shadows just feels that bit to blurry. In some ways it would be okay if the boxing glove, etc, where blurred too as then it would be a perspective/focus thing, but with them being solid, it just makes the snow looked that bit too much blurry.

I hope that makes sense and is helpful in future walls.