Apart from a few minor bugs and UX complaints I had, I think this game is already in a healthy state and the promise of it being fully playable to the end is true. All the major bugs of Piranesi appear to be fixed.
The game stays mostly faithful to the original, especially, although some UX changes/improvements were made. The game allows you to pick up clues (paper, book) but it restricts where you can place items now. Which is fine, I guess? The compass now works smoothly and is part of the HUD, although the arrows are not labelled (where is North?). Additionally, background music plays from time to time and several sound effects were added. This game clearly has seen major polishing, which is exactly what Piranesi neede.
Although it seems the project is not finished yet and still has many minor bugs, it's in a OK state already IMHO.
As for the gameplay, the puzzles are as difficult as in the original. My opinion on them is the same as for Piranesi (see the review there).
Unlike the original, this game still relies on color for some on its puzzles but it will now display the color of some blocks if you point to it for a few seconds. However, this still isn't perfect as some colored nodes in some rooms are too far away to be pointable. So for colorblind people this game is still not fully accessible. Hopefully this will get fixed later.
Overall, I give a recommedation, except when you're colorblind.