This is quite a nice little puzzle game, I've played through it in one sitting and it's been pretty enjoyable. It has some issues here and there though; if you have a controller connected the game will refuse to work with your Mouse or Keyboard, and if you're using the controller to play the game and accidentally try to use M/K again, the game sometimes stops processing any input at all. Alt-tabbing works fine though, so I don't know what exactly the issue is. Either way, you can tell by some of those little issues that the game is rough around the edges.
Anyways, if you're a big fan of puzzle games that don't rely on numbers or are deeply complex, this will probably give you a good evening's worth of entertainment. Don't expect anything long or any world to explore; this is just isolated puzzles one after the other

2 to 4 hours of gameplay and mystery
That's a bit too thin isnt it? I do enjoy most myst-likes however.
gotta give it a try.