I like it! However, sometimes I got framedrops to 25. It runs normaly on 75.

How did you do it? Did you use the texture as hightmap and model the relief or did you use a fancy shader to do that for you?

EDIT:

Now, can you imagine taking the Delphi Doom source (which uses OpenGL I think) and applying this relief mapping to the textures.
Yeah, give it a try!