Made a few more fixes and updates:

• The Basileus can now walk and run up stairs and slopes much faster
• The Energy Buckler now functions like a physical object instead of a weird phasing thing
• Brutus Canor now has a boss theme and introductory cutscene
• Brutus Canor now reacts to pain (with a higher pain tolerance than the average Bulldog), his mace now reacts to objects per the new update, and he even has a placeholder corpse
• A set of shielded Bulldog guards now block the entrance and exit of the arena, requiring the player to wound Brutus Canor to proceed

Still left to do:

• Fall damage
• Cutscene creation
• Figuring out how to make the game look a bit better
• The rest of the game