You basically need a timeline in front of you to understand what's happening. There's a lot said but not said by friends and situation. You have to be able to read the subtext to understand what's happening. The story itself it's a bit too much considering the time they had, but I think they did a pretty good job.
I can't really give a higher score because you don't get to know the characters or feel with them, so the emotional connection is lost.
If the series had concentrated on just one part of the story, would've been much greater.