This might not be a complete list, I worked on this the day I got my wisdom teeth out, but here's what I remember:
New item: the sideways corkscrew. It lets you spin. Sideways.
The unsimplifier item received an overhaul:
*It now functions more like a counter and less like a short ranged attack. The timing for it was tightened up considerably when standing still, but it should now work more consistently when moving.
*It can now reflect projectiles.
*Successfully damaging an enemy resets its cooldown.
Enemies and items now stop moving when they are more than 64 blocks away from the player. This should improve performance considerably, especially on longer floors.
Added one new card.
Level design fixes.