So this is from way back, maybe the mid-90s or a bit earlier, for PC. It was an adventure game where you controlled a character that was kind of a dark superhero. His power had something to do with night and I think had to get recharged with a dark liquid ... I think. The game was about solving some kind of mystery, kind of like Under a Killing Moon if you're familiar with that one. There was a lot of walking to different locations in the city where it took place, and a lot of talking to other main characters. I think a lot of those other characters had powers of some kind too. Any ideas, anyone?