New stuff: Bosses, items and stuff. Knock yourself out.
Recent additions:
Dedicated final boss who's hard as all hell.
Alternate 'final' boss who's also hard as hell and is also the eye of the Grim Reaper.
You have the great privilege of being able to see your own HP.
Also, you can see the names and descriptions of items you currently have.
Some new items and enemies and weapons.
A new pair of floors: Turbine.
Tweaked graphics. Will continue to tweak.
Most weapons no longer need to be emptied before reloading.
Hearts are sometimes briefly invincible.
Probably some other things.