Since Erkki has lifted the burden of me having to relive the ending, let me elaborate a bit on why it's so frustrating:
Spoiler:The game poses an interesting question: is this the real Jack the Ripper, resurfacing in New York? Or is this a copycat? I actually was interested in finding out the answer. The ending does not even answer this question; it is the ultimate cop-out. There's no point in asking a what-if question if you don't follow through on it. I was positive, when the game ended, that I had messed up and found the "bad" ending...then the press walkthrough let me know that there is only that ending. So after 12 days, no questions about Jack's identity are answered, and you never really catch him. Maybe they're planning a sequel, but it's just a terrible way to end the game.
