General discussion thread if anybody else is interested.
Technical details: maps lighting fully rebuilt with maximum settings, more expensive materials swapped in where appropriate, vegetation density increased, DirectX 8 mode actually working (!), running on Source 2009 for better dynamic lighting and other visuals. Gameplay details: various puzzles improved with better (but still subtle) prompting, various difficult-to-navigate areas improved with better (but still subtle!) guidance. Quite a few bugs both large and small squished as well. That disappearing-crosshairs thing? Finally gone. Exciting.