After receiving feedback from players, I have agreed to add some important changes to the gameplay.

• Items now home in on the player when they get close after about a half-second of spawning.
  
• A sound is played when an enemy carrying a tome enters the screen.
  
• The player gets extra coins from collecting items they can't carry any more of.
  
• Vampires have been revamped with much less HP and stay invincible when spawning in.
  
• Made various other enemies weaker and slower to balance the level difficulties and make it easier for the player to destroy as many enemies as possible.
  
• Decreased the number of spades from large groups of enemies that were made weaker.
  
• Fixed a few typos.
  
• Added a better hint message at the bad ending screen.
  

None of these changes invalidate scores. If anything they should make it easier to get higher ones.
I hope these changes provide a better gameplay experience. Enjoy!