2022-01-05 Update 2

More changes!

• Removed unintended solution from S.5
• Removed unintended solution from B.17 (by updating corridors on either side of it)
• Made B.12 reverse traversable after solving
• Made B.6 traversable in both directions after solving
• Fixed bug that allowed spawning a second player
• Fixed bug where a property of objects could vanish
• Fixed visual bug when removing foreign objects from another region 
• Fixed B theme overlapping an A themed wall in a distracting way