Shadows that show the player how far the wooden structure is away from the wall.
Also link specific colors and shades to specific things, along the lines of traps are always glowing, doors are X percent darker than other level geometry, etc. This needs to be consistent (at least within a level) to not confuse the player.
- Drop shadow (only on the wall not on the support structure)
- Darkened the platform-floor and raised it's contrast
- Extruded the outer edges of the platform floor by one pixel to separate it from the house
The house on the right (in your initial post, not the one in this reply) has more contrast and a better front to back brightness transition, but the railing support is too fat/obstructive.