Free dlc "4 knights" is incoming in a week.
It will allow you to play as any of the four main bosses of the game. The story and upgrade system will not change, but each one will act as their boss versions, so very overpowered :) This is a thank you for everyone who brought the game, a way to get back and punish all the enemies, and bosses.
Linux version news, I finally acquired the necessary second hardware to port it, the port should be done within a week if no issued arise.