I asked a couple more questions and got answers from the dev.
Berzerk2k2 1. How long do you think will a first playthrough through the campaign take?
2. How many difficulty options are there and what's the main difference between them?
3. Are unlockable guns etc. also available in the campaign as hidden secrets or is that stuff only for the firefight mode?
4. What kind of custom options does this game have (different window modes, fov slider, framerate cap options etc.)?
5. Since GOG does not have any kind of workshop support will there be any other way to not miss out on the content people will add to the workshop in the future?
6. What will the price for this game be like?
mattlarrabee 1) 2-3 hours first playthrough depending on skill.
2) 5 difficulty levels, each is a uniquely tailored experience depending on what the player is looking for. Enemy count, slow mo limits, ammo count, and player health are the most important things changed.
3) Only firefight for now, I was thinking about allowing it for campaign but decided to make it a post launch thing if people are asking for it.
4) has all the ones you listed, it has tons of options tbh I tried to incorporate a lot of requests from the discord.
5) for now GOG will support importing levels by placing the files in a folder, if there is demand maybe a central space could be made but nothing planned right now
6) Will announce price next week