Despite some (very minor) hiccoughs, this is a strong game.
I didn't play the previous releases, but started with the open beta of release 5. A solid effort, the gameplay is fun and novel, although at times I did try each object until I got to the right one. The experimenting didn't detract from the overall experience, however, and I never felt stuck.
Some of the sequences were stronger and flowed together better. Some of the simile-based puzzles early on felt a little shoehorned or simple, but they improve substantially as the game goes on. In particular, everything after (Spoiler - click to show)your first confrontation with Camino was strong, challenging, but fair.
The help system is clever and useful, although it may over-simplify some parts of the game, so I'd suggest not resorting to it as quickly as the tutorial might suggest. A few puzzles that I could have solved on my own were rendered easy by the use of it, and it felt a little bit like cheating.
The denouement had a surprising last twist--although it felt very straight-forward, there was a well-done plot twist your player could create. It doesn't substantially alter the game, but it is a hidden choice that really engaged my mind and made me consider the morality of my character, the story, and the other participants. It also made me wonder what I'd do in real life--all in all, a very well done example of choice in a narrative.
I highly recommend this game on the strength of it's writing, gameplay, and novelty.