The perspective on that house looks pretty solid. Try using some bigger brushes on it though, as now it is looking a little scratchy.
Anyhoo, I did a little paintover of your devil guy here. Hopefully it helps. Not going to list everything I changed, but a few major things included a more defined light source, thicker legs, and correcting the SSS (subsurface scattering). When it comes to light going through the wings, the blood will make that area very saturated and brighter than other areas in the shadow. Also, the veins will be darker there since they block the light coming through. Don't forget to include the red filtered light through the wings onto him and the ground.
"Complacency is the womb of mediocrity. " -- Jason Manley
"If you always put limits on everything you do, physical or anything else, it will spread into your work and into your life. There are no limits. There are only plateaus, and you must not stay there, you must go beyond them." -- Bruce Lee
The devil guy is looking really cool, i like the details on the skin. Although i feel that the legs
look a bit too different, His left one looks pretty hairless and more red-ish, while his right one looks hairy and a bit less veiny. Something you might want to think about .
Looking good for quick sketches. I think you should spend time and detail one of your observational pieces of art. You tend to learn the most from sitting down and really looking at your object. Keep it up man, loads of progress from these last couple of pages ;O!
It's nice that you're learning to suggest with strokes. That's something I'm trying to learn myself ;X.