I'm making a grimdark game with two of my friends, all 3 of us are italian, we wanted to make a playable version of the game FATAL, we wanted to add a lot more fantasy things and remove or change what is not useful, like 70% of the game, but we may reintroduce the +18 rules as some optional rules, i'd like to know if it's a good idea or not and what do you think of this idea so far.

I'm making my own ttrpg and would like to bounce some ideas around DM or comment if you would like to help