So good to finally be able to read the finished product! You did a good job with the ending, using Harry's dreams/subconscious to show what Snape ended up doing to the Harry in his world. Harry's sense of honor is very palpable throughout the story, from his determination to provide all information necessary to see Voldemort in the alternate universe defeated, to his decision to return to Snape even after the traumatic experience, if only to make sure Snape prevails.
Great ideas, from Dementors' Kiss to the possibility of alternate realities. And you should be proud of yourself for weaving these ideas into a haunting (in a good way) fic! Well done :)