After two weeks of attempting this I finally beat Mein Leben. Now i just need to grind out the helmets for the platinum. I had a death that crushed me emotionally two areas before the final boss at the Ausmerzer on Friday but had one more attempt on Saturday / Sunday and managed to get it done. Here are a few tips / strategies that I used that were different from Kreepers tactics.
I stealthed areas towards the start of the game to speed my run up always knowing an area I could run to and camp if things went south. Towards the end of the game I would go loud always in a good camp spot as I didn't want to risk being spotted and have enemies in-front and behind me. Slower but safer and you move onto next area with more health and armour.
Roswell Elevator: I never managed to get up the elevator without alerting the heavy and guards. I also tried the tactic of running up the elevator railing but was always spotted when I got off the top and killed or messed up the jump and died.
The tactic I used was kill as many guards, quietly, as I could, not the heavy, after exiting the train. If facing the elevator run all the way to the right and there is a ladder with a platform below. There is also armor there. Drop down and shoot a few times to set off the alarm. Enemies will either search the elevator platform (if it has come down) or go directly above you and they are pretty easy to take out. You know all are dead in the lower area once Super Spesh says something over the radio. Pick up all heavy laser weapons and drop then on the elevator behind the box on the back right. There should be 4 lasers form the heavies and there will be on the elevator itself on the left box. Start the elevator and run back to area with heavy weapons. Crouch and lean. The alarm will still be on so, as the elevator is in transit one robot will jump from the left (if facing in direction elevator is moving) and a heavy will drop down. From memory another two heavies will drop down and one more robot. You should have plenty of ammo in the heavy laser. Once at the top wait for the enemies to start moving around and pick them off along with one more heavy. I set up on the right as there is a laser turret that enemies can use that can hit you if you are on the left of the elevator. Sometimes the enemies stopped moving so I ran to the room in kreepers via and crouched next to the door and picked off the remainder of people as they came in and finally the commander. Much slower than what he does but much safer in my opinion.
Court Room: I used the strategy below which I found to be much safer as no grenades get thrown at you. After killing the heavies as shown in the video run to the spot where kreeper camps in his video and start shooting as he does to kill the dog. The dog killing tactic show in the video below is much riskier in my opinion and once the dog got me. I didn't die but it took off a lot of health. So in summary, I followed the tactic outlined below until after killing the first two heavies then I run behind the box as shown in kreepers video and killed the dog then followed the video below for the rest.
New Orleans: At the strat of Panzerhund ride, dismount and start killing guards while leaning past fench. Do this until the commander walks to you. If you stand you can shoot the guy behind the heavy dieselgun. The diesel gun can't hit you there. Just watch out for the heavies
At about 2:02 of kreepers video at New Orleans I used the following tactic. Melee the guy running near you as kreeper does, kill the heavy on the bus with a charged laser shot. Shoot the other guard near the heavy then run around the brick wall to where there are two boxes. Camp here and take out the raining guards and heavy, leaning past the cover. Continue as per kreepers vid.
Venus: In the first area stealth the first commander as keeper does. Go to the doorway at 2:11 of Kreepers vid and camp here. Kill the guy and heavy silently. Then start going loud. You will need to kill a few guards and three robots be careful as the robots may be on the wall on the right and use their heavy attack. They can be killed easy using lean. Once this area is cleared move forwards carefully to area at 2:13 in Kreepers vid and take cover behind the boxes. The two heavies will come from the front and with upgraded shotgun and rifle they go down easily. Enemies never cam form behind me. Take out the commander and continue.
The area at 2:18, I would always get spotted here. Just run down the hole in the floor and take the vent across. Kill enemies as they come to the top of the stairs. The heavies will be behind you as you come up the stairs. Walk up slowly and shoot in head with charged laser.
At the area 2:22 I used the battle walker shortcut. I actually screwed it up on my final run and set of the alarm and ran back to camp in the area where kreeper is at 2:22, take out drones and wait for guards to com down. This was very slow but eventually the commander came down the lowest level. I would not recommend battlewalker shortcut unless you have practiced it a lot.
At 2:36 of Kreepes vid go the right straight away and take cover and go loud instantly. Slower but safer in my opinion. You will need to kill 2 heavies and two robo dogs, however the path they have to walk to get to you in this spot is very long and you will have ample time to shoot them down. This will also give you the opportunity to get armour and ammo. If you stealth this area I don't think there are any armour drops.
The last section of Venus, it is crucial that you kill the shotgun guy to the right in my opinion as kreeper does. I found it very difficult to headshot him due to his back armour and I was always super nervous at this section. On one run I had the constrictor harness upgrade that you can get before venus if you want, risky but you get the ability of time slowing down when you are spotted, very useful when killing this guy plus you footsteps are silent. I then walked right up to the globe and shot it with silenced weapons.
The area at 2:52, go loud and don't use stealth. I tried stealthing this once but was spotted by the heavy. I got through the area but got shot in the back a few times when I killed the commander and went through the hole. Camp at the top of the stairs and lean right. Make sure you shoot the explosives below you first as you can be damaged by them. There will be a total of 2 heavies. Going loud here give you access to more ammo and you can go to the neat area with full health.
At the area at 2:58 as soon as you climb the ladder kill the two heavies with charged laser. Is you stay on the upper walkways the commanders have not spawned in yet so killing the two heavies will not trigger an alarm. When you do drop down however enemies will be an alert state as there are two heavies down but there will not be an alarm. Note, when an alarm sounds in this area the big grenade lobbing robot arrive on the elevator to the right. I tried kreepers strategy on the run that I failed and was spotted by a heavy early, took damage getting to the ladder and was killed climbing the ladder to next area. What I did on my successfully run was kill heavies from upper platforms. Equip Kampspistole in right one hand and shotgun in other, drop down, climb fence and shoot 2 grenades at door to right where commanders are and 1-2 guards, run forward and shoot another grenade at guard behind door that opening in front of you. At this stage the alarm would have gone off already, one commander will be dead from grenades as will a few guards. turn right and run to ladder to next area and shoot remaining enemies in front of you with shotgun, run left into room with ladder and kill last commander if not dead already and climb stairs. I took a little bit of damage from big robot but finished him off with a laser shot to the face after climbing ladder and going through duct. Enemies will despawn in this area so you can go back and stock up on ammo, health and armour. I used an kampspistole (no upgrades) as I ran out of grenades. When running to ladder change weapon to something else in case you accidentally shoot a grenade and hurt yourself.
In the area at 2:59 with the robot dog, I found that if you kill it as kreeper does, an alarm will sound almost every time. You can wait for the robo dog to leave and wait to shoot the commander from the stairs. If you kill the robo dog and / or the alarm sounds you do not want to the at the bottom of the stairs or ladder. There is a bad glitch in this area where the enemies can see and shoot you through the cannon on your left if you are on the stairs. You can shoot through it too but you can't see anything. So if the alarm goes off, battlewalker up the ladder (faster then climbing) and take cover behind the boxes at the top of the stair ASAP. When you hear the second robo dog lob a grenade with the electricity upgrade to kill it / slow it down. The robodog(s) and normal dog are the most dangerous enemies in this area in my opinion as if they get close they can deal a lot of damage.
For the final boss fight follow kreepers tactics. When in the H underground you can kill all guards whilst staying there. It takes a little while but they will all come down there. Take a shot or two at the door to draw enemies down. If none come down after a while ( I counted 5 laps running back / forth of the H) go and kill the two robots with charged laser shots.