Thanks to everyone that provided feedback in the forums! This update aims to address most of the issues raised.

Improvements

• The middle mouse (scrollwheel) button now drags the camera
• You can now press U or Backspace to undo
• Added a button to the settings menu to reset the entire puzzle
• Added a settings toggle to invert the light/dark colour scheme
• Added a settings toggle to disable error warnings
• Clues now fade out when they are surrounded by filled tiles
• Hints now give a better indication of which squares should be filled
• The default music volume has been reduced to 60%
• The game now zooms in on a hint at the start of your first session, rather than focusing on the bottom left of the board.

Bug Fixes

• Removed a confusing blue tile that could appear at the corner of the board at the start of a game.