👍 The puzzles.
👍 Minimalist design.

🤜 No tutorial (rather easy to figure out how it works even without a tutorial).

👎 Price for content (unless you're a puzzle addict).
👎 Severely lacking a "this number is needed"-mark function, at the moment it's just on or off, and while the smaller puzzles work without having this function the bigger ones get harder to keep track of.
👎 No special discount on the DLC bundle if you own the base game.