Several smaller fixes and changes to the Demo Playtest build.

Bugs:
- Fixed a rare soft-lock on the horizontal barrier
- Fixed statue saving logic
- Fixed all audio that lacked directionality / proper sound panning
- Fixed a rare audio bug when interacting with the ring buttons in a certain room

Changes:
- Added demo version number (0.1.1) to the pause menu
- Added saving notifications to the pause menu
- Added intro credits to the opening cutscene
- Changed geometry in certain puzzles to better communicate their purpose
- Changed some minor visuals