D3d_shadowdepth
Determines the color depth of the shadow maps. With d3d_shadowdepth = 24; the shadows are much smoother.
D3d_alphadepth
Sets the color depth for TGA sprites and bitmaps. With var d3d_alphadepth = 32; you won't see any banding.
Ogg Vorbis support
Ogg vorbis is similar to mp3 but it is free to use. Now you can create smaller sized games because the audio files will be tiny.
Unlimited terrain
The terrain size was limited to 100x100 vertices in the past. This limit was removed.