I agree with Nils, because I'm a Tomb Raider fan. I think this is a very good game in the Tomb Raider history, it took me some time to get all the secrets (even the one that doesn't seem to be a secret, on Pacific Islands!) but after have been playing I knew I didn't have lose my time.
If you like to see Lara in very diferent places, learning several skills, and test your brain and patience, so this game is for you.
The secrets in this game are not like the others. There isn't a special item to collect (no Dragons or something like that), you have to perform tasks like getting some ammo, or health packs, hidden in secret places.