Huge stealth game fan, but I have some questions about the game

What kind of save system the game has? quicksaves/manual/checkpoints or restart the whole mission.

What about difficulty modes?

what type of procedural gen did you use, is it random map design/enemy placement thats handcrafted by the devs (e.g 10 types of scenarios randomly chosen) or completely random?

Finally will you also be releasing it on GOG? I'd prefer owning my games there

Thanks and good luck on the game.