Possibility to play as good or evil or anything between, people today are so sick of hollywood style cliché stories where good always wins and outcomes are too easily predicted. Which makes me hope your story will have big surprises, so big that anyone who tried to achieve for example good ending of the game, might actually fail it even if he/she chose all the obvious "good" choices during the story, so that he has to try again.
I like shocking and surprising moments, and they can be very impactful. But I don't want any final outcome to come as a
complete surprise. Plot twists for their own sake are...not great. There should be hints and clues along the way such that, when any plot twist happens, everything you've experienced is recontextualized and it makes perfect sense why and how things would end up this way.
An ending of "Things end terribly for you because you chose Good options even though you had no way of knowing those options were leading to this outcome; sucks to suck!" would be unfulfilling and frustrating imo.
