Just a few things I wanted to point out since many players are actually asking repeated questions about some aspects of the game.
I don't understand your developer commentaries, it's in french!
Just turn on captions/subtitles in the sound options tab of the game.
I'm stuck at level <insert level number here>!
There's a section of the forum dedicated to help you if you're stuck somewhere in the game, take a look here :
/forum/viewforum.php?id=5
That 19th test chamber is bugged out! I didn't take the cube!
Maybe you didn't take the cube, but you surely didn't look and listen carefully at the hints. The 18th and 19th levels are closely linked, just look around and search for a hidden path. There's no need to cheat or reload a saved game.
I spotted a bug somewhere in the game!
There's a section of the forum dedicated to bug reports, take a look here :
/forum/viewforum.php?id=6