- Estimated achievement difficulty: 5/10 [Achievement Difficulty Rating]
- Offline: 45 
- Approximate amount of time to 1000: 15-20 Hours [Estimated Time to 100%]
- Minimum number of playthroughs needed: 1 [with save manipulation]
- Missable achievements: Yes
- Does difficulty affect achievements: Yes
- Unobtainable/glitched achievements: No
- Extra equipment needed: No
Lead the revolution of the Orcs and Goblins! In a world at war, the vast Empire of Men tries to extend its domination over the territories of the Orcs and Goblins, who are systematically persecuted, enslaved and massacred. Through this great role-playing game, lead a fearsome Orc warrior, and a Goblin master of assassination and stealth. You have been appointed to fulfill an extremely dangerous mission, deep in enemy territory: to kill one man...
Step 1: Extreme Playthrough
All of the difficulty achievements stack, and you can save whenever you like, so with a little save/reload magic, you can get all the achievements in this game with one playthrough on Extreme difficulty. I would highly suggest following the Road Map for this game written over at PST found here, which will lay out exactly what order to do all the game's quests, and when to save/reload, so you can get all the achievements in one run. The only thing I'll suggest you ignore is that it says the game requires two playthroughs. The writer over there had some incorrect info regarding the "Big chest lover" achievement which can indeed be done in one playthrough.
I will say Extreme difficulty is no joke, and you'll need to be very careful to succeed. Here are some tips I found helpful during my run:
- SAVE CONSTANTLY! You should save after every battle, and when assassinating people with Styx, save after every single assassination. It's annoying to kill 2-3 enemies and then get spotted and have a fight you can't win. You can also die very easily, so don't forget to save after a battle so you never have to redo it.
- Assassinate as many enemies as possible. Use Styx to clear out any fringe enemies, whittling down the total number in any given area before you get caught and have to fight. Because you take a lot of damage on Extreme, you'd much rather have only three enemies compared to five.
- Target the same enemy! You can use to switch the character you're controlling, then / to select an enemy. Always have both characters attacking the same one. The quicker you can get less enemies in the fight, the better.
- Kill "normal" enemies first. To compound on the last point, always kill the weakest enemies first. Don't spend two minutes killing the boss while his dogs and basic swordsmen take off half your health.
- Upgrade defensive abilities early and often. I used Stunning Punch as much as possible with Arkail while he tanked damage, with Styx starting a fight using Sharpshooter and then letting him auto attack.
- For your attributes, put everything you have into Stamina for Arkail to boost his health pool, and Strength with Styx to increase his DPS. You'll use Arkail to stun and get in big hits while Styx picks away from afar.
- Try to upgrade gear often. Always be searching for bags/chests to loot (which will help for "Big chest lover") and use trade points to always upgrade your weapons. Again, killing enemies quickly is paramount. You can likely skip upgrading your armor, but if you have extra trade points it certainly won't hurt.
- If things go south and Arkail goes down, run away with Styx! Use your revive shout on him, and continue running! He'll get in a few more hits, and if all the enemies turn to focus on him you can throw a few daggers with Styx, then rinse and repeat until the fight is over. You can take on really bad odds with this method.
- Throw Styx to start a fight. Don't underestimate this move. You can throw him at a crossbowman for example and kill them in one shot, and this will put him on the edge of the fight to have a nice spot for his ranged attacks.
Step 2: Easy Mop Up
There are two achievements that you may not get during your main run of the game. The first is the aforementioned "Big chest lover" though if you're doing every side-quest and checking every inch of each map, you should have no issue with that. The other is "You crack me up" for killing 15 enemies while Arkail is berserk. He takes a lot of damage when he is enraged and will die quickly if there are still a few enemies left who are attacking him. Both of these achievements track across all save files though, so start a new game on Easy if you need to and mop them up.