My attempts at the Ultimate Spy Achievement in Wolfenstein II: The Diaries of Agent Silent Death. There wasn't really any good strategies that I could find so I am posting my last 5 attempts in Mein Leben difficulty so people can get a general idea of my routing and strategy (A good chunk of the basic concepts and general strategies have been taken and adapted from Kreeper V's guides for the main game Mein Leben and Gunslinger Joe Mein Leben, so shout out to him for those).
The successful run starts at about 22:00 into the video, but I recommend watching all of the runs to get a better idea of the strategy I was going for.
If you die, don't forget to change difficulty back to Mein Leben before you start.
1. Like the other two DLC, to get the Mein Leben difficulty achievement you only have to finish the third volume.
2. PRACTICE!!! Go through the level in I Am Death Incarnate at least once. Being able to figure out where enemies spawn and how they act and move, plus having saves makes this much more tolerable.
3. Agent Silent Death has an ability essentially the same as the constrictor harness in the main game. You WILL need to take advantage of this ability in this level. You seem to have no time limit on how long you can stay constricted, so up until you blow up the life support for gamma station you can take as much time as you need sneaking around.
4. Don't bother picking up any armor or weapons (other than any pistols and pistol ammo). You will be dead in about two shots even with full armor and the other weapons will alert everyone in the map, which will cause bullets to be forcefully placed into your skull, which is bad.
5. Aim for the head. With the pistol this should always be a one shot kill if you hit them right. You want to save as much ammo as you can because you kinda have to lay into the general to kill him, so extra ammo is good.
6. Ignore the Supersoldaten and Panzerhund, you wont be able to kill them, at least not without dying immediately after.
7. Make absolutely sure you are NOT seen by the Laserhund (The annoying fast dog robot with a laser face). It will ruin your day. It will despawn after you destroy the stations life support, as long as you don't alert the general before or while doing that.
8. Kill as many of the regular guards as possible and if you can, kill the generals dog. They will also ruin your day if you leave them.
9. After killing the general, book it for the exit, and pick up a health pack on the way there (see video for where I grab it).
I kinda messed up my strategy for killing the general at the end but it still managed to work out. My original plan was to kill the dog when he is next to the general, then turn to the right and exit out into the large hallway. Wait for the general to walk in front of you, then aim and lay into him with the pistol. Once hes dead book it for the exit, stopping in the first control room for a health pack.
Hopefully this helps someone get through this since it can be a bit of a pain.