This game is a masterpiece. It's one of the best games I've ever played, and it's one of the rare games that I know I'll still be remembering in 10+ years. I've played it when it came out (2012) and I still shiver whenever I read about it or hear the soundtrack.

A few things to consider just so you're not disappointed :

1) You're buying this for the SP campaign. MP isn't great.
2) The campaign is maybe 7 hours long. It's the perfect length for this kind of game.
3) Since the game is "short", I HIGHLY recommend trying to beat the game in a short period of time. Ideally in 2-3 sessions, unless you're willing to clear it in a single sitting which I'd recommend if you can. The story is intense and can be quite confusing, so waiting weeks between 2 gaming sessions could have a negative impact on your appreciation.
4) Don't read anything / watch anything about the story or pretty much anything about this game before playing (even some reviews). Spoilers would ruin it.
5) Don't give up on it too early because the first hour or so is average at best.
6) Should be obvious but anyway, make sure to play with sound on (music, sound effects, voice acting). It's not a game you want to play while the TV is on or while talking on Skype.
7) Pay attention to the little details. Hints : Title screen, voice acting, flow of the game, etc. This is part of why it's a masterpiece in my opinion.
8) If you're not great at shooters, don't hesitate to play at an easier difficulty. Seriously you're not playing this for the challenge / gameplay. Some parts near the end can be annoying, and there's no real point in playing this at a difficulty where you'll have to restart often. Just make sure you're comfortable for the ride and enjoy it.