Light knignt

The floor below in the top of the castle level has no collision, you can fall through it and die.

Two music tracks are playing in the menu and boss health is shown at the bottom of the screen.
The portal in the boss room can be activated before defeating the boss.
The gate in the hub area can be opened before visiting the towers.

Sorry guys there was a glitch where you enter a portal it would be the same level just played (just fixed it in new update