Finally after a long wait here's a new demo.

Features:

- full FPS mode with collision detection
- possess creature mode 
- whole level drawn in FPS
- when in FPs mode the ceiling gets drawn
- dynamic building and selling of doors
- dynamic selling of the rooms
- simple GUI, you click on the button and then you can build/sell doors

......

Things you can do in this demo:

• Click on the door button and build doors.
• Click on the biledemon located near the heart to goto possess mode.
• When you are in possess mode you can walk throung doors you built previously.
• Click on the sell button to sell doors, rooms,...
• etc..

Report back to the forum any bugs you happen to find. And remember this doesn't represent the final state/quality of the game.

And here's the link to download.

A sample picture: