The entire game is actually from Simon-3's perspective (spoilers!)

[grrrz]

well to be fair
You play as Simon-1, then the 2, then the 3, (and the 4 in parrallel after the credits). That's pretty straightforward, no need to invent a twist. The story chooses each time a "branching" path for us, and we we learn through the game how simon-1 lived his life, and for the 2 we have to choose.
what's good about the story is its elegance, it's good, but there is no big artificial twist at the end (a few small ones but they're not big shocker).