Absolutely brilliant and original with a great difficulty curve while continuing to surprise you for tens of hours. Difficult but fun, I found some of the final regular puzzles to be the best. It’s also a free demo right now, but I would have happily paid more than £15 for the current release alone.

EDIT: Yep, full release delivered. I'm not crazy on the added story and dialogue but the puzzles are NOT lacking. The rabbit hole goes deep and it never feels repetitive. One of the best games I've ever played.