I just finished Cold Darkness. Wow that was incredible! I absolutely did not expect a mode relegated to the crappy challenge / score attack system could be so fun. I guess it helps big time that Cold Darkness actually has save files / save points. You can quit at any time and resume.
More importantly, the puzzles are what impressed me the most. I don't think I've ever in my life playing video games seen such a neat implementation of If > Then puzzles... For example, "If the fuse boxes have less than 6 red fuses, then perform task Y. If not then perform task X."
What was so lovely was Nadia's voice acting too. I loved how she's reading from her manual, giving you the precise If > Then instructions, and then goes "No-no-no-no stop Lara! Stop I was reading the wrong page! Let me restart!" Heh, it was great. I loved the nervousness in Nadia's voice. Whenever you ask her to repeat the If > Then instructions, she says "What? Again? Okay let me pull up the page again..."
The ending of Cold Darkness was annoying though... those damn enemies kept bugging me / hitting me whenever I was trying to line up a shot on the end-game targets. Urgh.
Edit: They should make an entire co-op game entirely comprised of puzzle-solving game play with If > Then instructions. Imagine two different co-op partners walking around a haunted house full of dangerous contraptions/puzzles/traps. One co-op partner has tools (wrench, screwdriver, hammer, etc...) and the other co-op partner has an instruction booklet. The co-op partner with the booklet is the only person who can see the instructions. The other co-op partner is the only person that can actually physically solve the puzzle or interact with the puzzle... Writing it out like that seems boring, I just realized - but I'm just really floored by the If > Then puzzle structure found in Cold Darkness. I want more games with this.
Here's a game that sort of has that concept:
https://www.youtube.com/watch?v=tn71KuoUTpE&feature=youtu.be.