Spectres can now appear using the old 'fuzz' effect, or as a dim translucent version, which looks much better especially in 24 bit modes. Optional clock ensures you don't spend hours in Doom, and an alarm can remind you of this. Optional 'quick' status in full screen mode, providing your health, key cards and ammo. Monsters remaining and secrets discovered can be displayed in the automap. Secret areas can give notification when entered.
Sound effects can now have their stereo balance swapped.
CD Music can be used instead of internal MIDI music. Atmospheric music makes the music react to the events in the game. CDDB to provide a track and CD naming. Can end level when a player is a number of kills ahead of all others, aka 'x kills ahead wins'. More robust network code should now never leave the driver and the game unaware of one another.