The mdf walls have been painted and wallpapered, I did some touch-ups with wood filler, the windows completed with trim, and ribbon has been used for baseboards. As I do things, I often think here's the first and last time I do a shell floor, the first and last time I do oval windows... The end product works out but there's some swearing in the execution.
The floor was a bit of a project in itself - the main components are mdf, shell pieces bought at Michaels, and Richard Stacey Mortar grout mix (cement based adhesive). I had bought the grout mix for Hogwart's stone tiles but decided to use it on this instead. The first time I laid out the pieces, puzzle-like, it didn't take long at all. However, transferring that pattern from the cardboard to the same sized piece of mdf didn't quite work and the second time the layout was slower going. I sealed the mdf with a coat of watered-down glue before gluing down the shells. The mdf simply rests on top of the birdcage bottom tray. You can see some of the steps below: