After further testing, it became clear that neither Level or Difficulty bonus multipliers were required. You can still expect to score higher on harder difficulty modes, but the increased score will result from increased Chain & Speed bonuses. This was always the case, but it's pretty clear that it's working better than ever.
It should also now be much easier to understand the base score for an enemy or an item and understand how the multipliers are being applied.
Level Multipliers
All level multipliers are now: SCORE x 1
Difficulty Multipliers
All difficulty modes are now: SCORE x 1
A Few Extra Improvements
All levels now contain secret items of some sort. As always, there are partially hidden items and there are triggered secrets. Triggered secrets can now be found at the end of all levels starting with Level 3.
Weapon Aiming
Based on player feedback, weapon firing is now more responsive than before.
More On The Way
Additional features are in the works, but it's a little too early for an announcement just yet.
Stay tuned for more updates!