It looks very blocky, empty and you are using the VERY outdated standart.wad or other not really tilable textures.
All in all it looks similar bad as my first project, though your level seems to be a bit bigger

Lite-C Tut. 1 Lite-C Tut. 2 Lite-C Tut. 3 (en)
Shader Tutorial (ger)

http://www.slindev.com