I know that in the current climate of the gaming industry, everyone is glamouring for hardcore games that don't hold their hand, but I don't think Natural Doctrine is what you're looking for. The game isn't challenging so much as it is just inconsistent because the enemy rules are seemingly made up as it goes along. It just isn't enjoyable to play, and that's a really big failure in a game like this.
If you enjoy classic cold war era spy action, Counterspy is oozing with style and integrity. The enemy AI is a little inconsistent and can cause frustration with the defcon system, and the game is maybe a bit too short, but these things don't bring down an otherwise great game.
Developer The Astronauts has proven that you don't need a AAA budget to create a game that is not only beautiful, but also thought provoking and atmospheric. The game's only pitfall is how short it can be if you are only interested in the main story, but I would say it is worth a second play-through to discover all of the hidden investigations and secrets. If you are into Lovecraft or Poe and appreciate a macabre mystery with heavy atmosphere, you owe it to yourself to dive into the world of Ethan Carter.
Last Light stands out as the star of the package providing a well paced journey of redemption through the dreary and isolated world. In spite of it's vast improvements, 2033 just doesn't hold up as well and can feel like a slog due to tedious encounters and repetitive enemies. I would recommend playing them both but if you have to choose, go with Last Light. The story does a good job of recapping 2033 and it is a much better game.
The bottom line here is that if you have a passing interest in Tolkien's work, and you liked the Arkham or Assassin's Creed games, then you owe it to yourself to give Shadow of Mordor a shot. As for avid fans of Tolkien, the retconning of certain pieces of lore might upset you but this is hardly the first time a Lord of the Rings game has done that, and at least the "game" part is actually good this time. Just don't go in expecting a story on the scale of The Lord of the Rings or detailed environments, they just aren't there.
Although it may seem like a daunting task at first, navigating this enormous castle and defeating the enemies within is a challenging and satisfying adventure often missing from modern games. Learning and mastering the controls while your character gets incrementally stronger will make you want to spend hours trying to get just a little bit further until can take on the bosses. Whether you have nostalgia for retro games, or are just curious about them, Rogue Legacy is a perfect entry point for newcomers.
Overall Alien: Isolation is the game Alien fans have been waiting for. In spite of the numerous broken promises in the last 35 years, Creative Assembly has successfully formatted a love letter to fans of the franchise, one that has taken far too long to get here. A golden standard has been set for all future titles in the Alien universe. Simply put, Isolation is the definitive Alien game that no fan should miss out on.