Honestly, I think it's a great game for sure and I am an absolute sucker for story but (and this is just for me on a personal level) I'd argue it's a little overrated.
It's probably down to my own personal preference is part of the issue. The story is brilliant but it isn't one that engages me entirely. The gameplay suits the game but that doesn't make it anymore more satisfying, I don't feel like I had done much whenever I fire a gun or use a weapon particularly. Admittedly exceptions to this are the gravity gun and the crowbar, where they both feel powerful (ironic considering the crowbar is...a crowbar).
I wouldn't ever call it "the best game created in the world", I have other games I call that but I would say it is a very good game.