its especially strange when one of the characters you meet (this is very light spoilers but its also a complete vampire trope so I'm not even going to spoiler tag it) is someone that only kills bad guys (I told you it was super cliche) and yet if you even kill 1 person, you are imediatly locked out of the good ending. It's like
Gamer @ Heart says, you gimp yourself so much that the best way its probably to level up the npcs (fidning out info about them, doing their side quests) and then chow down on them for the xp and ignore the "good ending".
In fact, this got me thinking how obcessed we have gotten about endings, here is a game that you actively make it WORSE to play just to get this fabled "good ending". Yeah... no. when I get back to the game Im eating dem people (one of the reasons I stopped playing was because I was already feeling the difficulty from being so nerfed, even jut a few hours in)