From the announcement:
This WWII European style building is the first in a new series being introduced by GameCraft Miniatures. We are calling them "Hybrid Kits" as they include a facade that is a resin casting with excellent raised details, sides and back are simple laser cut and engraved MDF. This puts the maximum detail on the face of the building and keeps costs down.
Using MDF for the sides, back and top allow us to release this kit at about 1/2 the cost of an all resin kit and it still looks great where it matters most, on the front of the building.