Fix Update

Fixes and Improvements:

-Added mouse sensitivity settings.

-Fixed an issue where the player couldn't return to the main menu after selecting the difficulty level.

-Fixed numerous minor in-game bugs.

-Fixed the Slenderina spawn issue where she would fall through the ground, making her invisible to the player, who could then start taking damage by looking at the floor.

-Added a global counter for all collectible items (keys, candles, books). By pressing Tab, the player can now check which items have already been collected at any time.

-Slightly optimized the lever logic that powered up the entire map, which was causing sound-related bugs for players.