If you are in it for the plot, there are people who record entire play-throughs on YouTube. You can just sit back and watch. Why bother with the puzzles at all? They are very complex. Just doesn't seem like a good use of time.
It's a puzzle game, first and foremost. Some of the most devious, complex puzzles I've ever seen in a video game. Solving one of the rooms without needing any help makes me feel like Einstein! That feeling is why I'm playing. To me, there are very large cut-scenes in between the playable parts. They are certainly entertaining, but the 'game' part is why I play.
I didn't think I would like the game, but took a gamble, and after solving two rooms, I am hooked, and invested.
There are a lot of great games. Can't play them all. Don't really care if I miss out on the meaning of some plot. The game seems to have an interesting enough plot as it is. Ignorance is bliss, I suppose!
I'm enjoying it just fine without having played the first game. The puzzles are in no way related to that game. I think character motivations will become apparent as you play. Kind of nice that things are mysterious. I think this game stands on its own very well.