(as of the July 2019 63-level demo)
It’s a very good puzzle game (even in its current demo state).
The mechanics are good, and in particular non-trivial puzzles are well-thought-out and for some quite challenging (I have to admit I had to sleep over the penultimate one to solve it (⌒_⌒;)).
There are a bunch of minor things to improve, some tile mechanics could be refined a bit (maybe simplified for some?) and the difficulty curve should be tuned a bit too, but the developer seems to be already aware of all this.
Finger crossed it keeps getting refined ;)
And thanks! I had a great time playing with the demo.