- Estimated achievement difficulty: 5/10 [Achievement Difficulty Rating]
- Offline: 58 
- Approximate amount of time to 1000: 40-50 hours [Estimated Time to 100%]
- Minimum number of playthroughs needed: 1
- Missable achievements: Gourmet Socialite (10G) and Said You're Sorry (10G)
- Does difficulty affect achievements: Yes [Must play on Nightmare]
- Unobtainable/glitched achievements: Weakness Finder (10G) and Treasure Hunter III (60G) are unobtainable, Crystal Fruits IV (60G) can be glitchy
Note on Difficulty Achievements:
Note on Unobtainable Achievements:
At release, the achievement Treasure Hunter III (60G) does not unlock despite meeting the requirements. It is also believed that Weakness Finder (10G) does not work, though the requirements are vague so it's possible we just don't understand what is required - however no one has unlocked it yet.
Note on Glitchy Collectibles:
The achievement Crystal Fruits IV (60G) can possibly become unobtainable due to the game's VERY glitchy spawns and tracking of the collectibles. At any time, most notably in Chapters 1 and 2 (possibly only in these chapters), the collectibles can simply fail to spawn when the map area loads for the first time. Unfortunately, the only solution to this would be to load a save prior to loading the map area for the first time - as soon as you set foot into the new areas, the fruits will either spawn or not, and reloading the map or fast traveling and coming back does not force them to spawn if they did not initially. You will need to check for all the spawns immediately upon entering the area and reload if any failed.
There is also a second glitch to this, and that is sometimes upon collecting a Crystal Fruit, it will not be added to you inventory. So even if you do get lucky and all 100 spawn, you could end up losing a few without realizing, and since the achievements unlock when you turn in the fruits, you'd be locked out of the final achievement for 100 fruits. Because of this, it is highly recommended to save prior to interacting with each collectible, verify it showed up in your inventory properly, then save again after. Repeat this for every single one, and be sure to keep a separate save prior to starting each chapter just in case one of them failed to spawn in the first place.
Step 1: 100% Run on Nightmare
Once you complete the story, you can lower the difficulty and return to any area in the game to clean everything up that you may not have done (likely the weakness achievement and maybe some fruit collectibles).
Step 2: Easy Run - Mop Up