Oberty

Easy to learn, hard to master kind of thing. Don't let simple designs and pleasant music fool you, there's a ton of puzzles here and if you're up for the challenge you'll have a great time, I haven't finished the game yet, about 30% done but I really want to savor the rest while being 100% sure I want to recommend it already. It's not that kind of puzzle you speedrun through anyway.
Now the closest comparison I can muster is a Rubik's Cube, the concept is similar but this is way more versatile and oh boy, so very addictive. I end up just creating shapes for the fun of it sometimes. It's also very cheap so you won't loose much if you're unsure but honestly one of the best puzzles I played on Steam so far, well-balanced and fresh even after a bunch of levels.

UPD. Finished it and loved it to bits!

After 50 hrs I finished this game and I can recommend it if you liked game similar to it (there are not many of them)
Now, i really liked this concept from the first time I played VOI and Zengrams so I felt mostly at home while I was playing Oberty. I doesn't do anything new but that is not a big deal. There is a lot of puzzles and some of them can be very tricky, Every stage has a nice intro and the levels gradually become harder. There is not much else I can say, you get exactly what the trailer shows. Few minor negatives would be a very short track that plays on a loop (really annoying but you can turn it off) and some of the puzzles are repeated in different stages (just 2 or 3 of them)
I really like these kind of puzzles and I can recommend it if you are into this kind of stuff.

EDIT : I would like to thank the developer for adding features for people with visual impairment.

There are two types of puzzles: good puzzles and bad puzzles. A good puzzle gives you all the tools you need and lets you figure out how to use them; a bad puzzle expects you to have brought your tools from home. Oberty is an excellent example of a good puzzle.

You don't need any obscure trivia knowledge to complete the game, you just have to pick up the tools the game gives you, and figure out how to put them together. And once you've played with the tools long enough, you'll learn some interesting principles about how these tools work, and you'll be able to use those principles to solve harder and harder problems with increasing speed and expertise.

And occasionally, you'll be thrown into a puzzle that you have absolutely no idea how to solve and no idea where to even begin. So instead, you throw your whole toolkit at the wall and see what sticks. These puzzles are less good. There might be some clever way to solve them, but I never figured it out.

Other than that, there isn't much I can say about this game. It took me 9.7 hours to complete, and I'll probably never play it again. But that's just the nature of puzzles. And you either like puzzles, or you don't.