If you have bought Rise of the Tomb Raider season pass, then you are safe, because this is part of it. To clear some confusion that goes around the internet, 20 Year Celebration Pack is not a simple skin pack. Yes, it has some weapon skins, new outfits and even hilarious new model for Lara - recreated model from the third game, which is out of place and awesome at the same time. The meat of this Celebration Pack are Croft's Manor that is in Blood Ties and Lara's Nightmare. Blood Ties is pretty interesting story DLC that is a throwback to classic Tomb Raider games with all the puzzles and finally being in the manor. It is awesome, well paced and with some cool puzzles, but the only downside of that is the length, which is around 2 or 3 hours. Doesn't sound bad, but when you play it, you'll wish there was more. As for Lara's Nightmare, it is simple horde mode, where you slay waves of enemies. It is competent, but personally, I don't care much about things like this. Overall, nice package, although I think you're better off getting either Season Pass or 20 Year Celebration edition if you don't have the game. Content itself is high quality and I recommend it.