Great game. The it starts extremely easy. The first dozen puzzles are probably there to show introduce a player that never has played a puzzle game to the concept and the controls and to show off the animations. The puzzles get more difficult in a nice progression, although there are some sprinkled into the mix that are easier (for me) as a quick break between more difficult ones. New mechanics are introduced with a simple puzzle – there is no text at all – only pictograms, but they work. The controls including key bindings are introduced via popups that function as a progress bar. I've recently played the demo of a different puzzle game where the developers did not manage to make clear icons which features a very confusing menu that seems to cause trouble for many players, so well done.

I have completed about 50 of the 160 puzzles.

The Linux version (thanks!) runs without problems on Arch Linux on my desktop, but my laptop's integrated Intel GPU is clearly underpowered (even the intro credits are in slow motion).