I killed the boss, its bullet pattern was less impressive than the one in the screenshot ;) .
The game is cool, it controls wells, the enemies and bullets are very well noticeable, which means the darkness just reinforces the atmosphere without hampering the gameplay. Movement and gunplay feel good and manipulating enemy behaviour is just doable enough that the game is approachable yet still fun partly due to the level openness, you won't just super easily have every enemy follow you until they die up to point, some will generally choose another path not only when you enter a level but also a little bit later. I like the sanity mechanics, the choices are not obvious.
Well done, thanks for sharing.