Middle-earth: Shadow of War

I'll preface this guide by saying the final score you receive at the end of a run highly depends on SPEED, which in having a fast attempt also results in a higher multiplier. You have to receive a gold trophy at the end of your run for this achievement to pop. I recommend playing through Desolation of Mordor once before to acclimate yourself to the new region and new traversal systems. Once you beat the story you may now start a new run that has no missions, just outposts and the fortress!

I ran on Nemesis difficulty which makes enemies smarter and do more damage. Some captains even have a NO CHANCE, so if you die your run is a wipe. My strategy is as follows:

I completed the outposts in a clockwise rotation whilst going for the mercenary discounts first. Then go for extra health pack skills. By your third or fourth outpost you'll most likely be able to afford a Legendary Mercenary as long as you have the three additional discounts!

Once you have all the outposts, I recommend targeting the Warchiefs with either the best disable for the fortress or the most bodyguards to save time for the Siege, of course. I also implore you to fill the outpost slots with the cheapest mercenary you can find so there isn't another orc captain there.

HINT: Constantly update your gear that you find in the field. There are insane abilities you can find that almost cripple the entire game's combat system such as earned might for damage done to your allies by enemies, which delivers you endless might for combat executions.

Also, when choosing mercenaries, make sure to pick the ones with the best abilities while ensuring these potential bodyguards don't have skills that counter each other. I was very lucky to have a Legendary merc that had poison bombs and a reduced cooldown. He completely destroyed adds and captains. Starting off can be difficult, but since this is a Middle Earth game with it's Nemesis System, make sure to exploit the captains' weaknesses.

Now, I didn't kill all the Warchiefs, just the strongest ones or the ones with multiple bodyguards to lighten the load for the final assault! Basic idea for this achievement is to get the best mercs possible the quickest because once you get two or more legendaries, you can SPAM THEM FOR EVERYTHING. This could be for remaining outposts, Warchief missions, and the grand finale.

I almost got screwed going into the overlord fight because I didn't dismiss my bodyguards before I went in, so I had to kill Takra only with Serka. I'm assuming the Overlord is a constant, so he is immune to nearly everything, but I kicked his ass by using a combat execution which dazes him because of his fear of combat executions. Once again, make sure use your silly Batclaw to escape and parachute away only to come back and stealth attack the captains(IF NOT IMMUNE). Pretty useful and cheesy.

Here are my stats for achieving Gold:

SCORE: NEW HIGH SCORE. 232326 GOLD
XP Gained 63946
Outposts Captured 5000
Min Difficulty (Nemesis): x2
Run Time (01H:31M:06): x17

DISCLAIMER: EVERY RUN IS DIFFERENT
RNG could play into how I achieved this first try.
Different Mercenaries
Different Captains with different exploits and weaknesses

I havn't tested it, but you could theoretically start a new run, check out the metal of your mercs, and discern if you should rather go die and start a new run with potentially better abilities for your mercenaries.
Good luck everyone! Happy Hunting!

EDIT:
According to belgianplayer1, they scored a Silver Rating of 221,618 which could very well mean the threshold for Gold is 225,000. If anyone finds this to be inaccurate, then please don't hesitate to post your times and scores in the comments below!

My strategy is simular to HollabackGamings but we definitely did somethings different.

For one I played on Gravewalker difficulty which if you get hit twice by even the grunts your run is a wipe.
But yet on my second attempt on it I managed to get 500745 as my score and it took me between 1H and 1H 20Mins. This is for tips on how to complete it on Gravewalker difficulty.

Heal everytime your health is below three quarters.

On your first run collect all of Torvin's items and return them (these are incredibly useful and you get an achievement)

Try to kill everything from a distance and stealthily unless the Captains traits force you to fight head on. My strategy was flying above the Captains, stealth attacking from above then getting out of there as fast as possible but had to regularly improvise.

If there are a few captains bunched together shoot in the middle of them with a poison bomb then shoot a fire bomb, this causes Balefire which is devastating.

Put epic mercs down as outpost leaders because in the final assault common mercs die before getting inside the gates.

For upgrades:
1. The one that allows you to see Outpost Captain's traits.
2. The one that allows you to see normal Captain's traits.
3. All four of the healing upgrades.
4. It doesn't really matter from here but I suggest the bolt or bomb upgrades.

Constantly check for captains immunities and vulnerabilities, if one is immune to arrows but vulnerable to stealth its wise to stealth attack them and if you have full might when you land, use your combat execution on them or a a vulnerable captain then spam the A button to jump over the grunts heads until you find a place to latch onto and escape, then reset and do it again until they're dead or you've captured the outpost.

I only had one bodyguard and he was legendary which I bought just before the assault, activate him once in the final room where you face the overlord as this will really help.

I didn't kill any of the Warcheifs before commencing the assault so was forced to kill all four catapult graugs (which needed to be taken out quickly) and the captive drake. Your mercs should clean up the enemy Warcheifs so just swoop in for an easy kill or taking one of their defense points.

For items make sure to check them before activating them as one halves your health which on Gravewalker is a death sentence. But make sure to constantly update your items.

When in a 1 on 1 with a captain (this applies for the overlord) use your chain to reel them in to you then when they're down ground execute them, rinse and repeat until you have enough might to do a combat execution, then continue until they're dead, this way you shouldnt take any damage and should clean them up quite quickly.

Really handy trick by Place of Power: "When your about to die while in the kneeling position you can dashboard/quit game and it'll be like nothing happened, the map will still be blue. While I was about to die while kneeling in the overlord room I quit the game immediately and it only took me back to the start of the siege... the map was still conquered and I got my gold rating."

Goodluck guys and I hope this helps.

Edit: added photo as evidence of my score.

http://s1380.photobucket.com/user/Halo0006/media/20180514_22...

Edit 2: was asked for extra tips so added them in here too.

Edit 3: I was given a really handy trick by Place of Power to add in here.

I will show you how to get gold on nemesis difficulty.

Props to Hollaback and Halo for their advice. I followed some of their methods while adding my own based on play style and ended my run in 33.5 minutes on nemesis scoring 390,155.

Starting the run I took the outpost on the bottom left. Bombing the living daylights out of anything that wasn't human. Taking this outpost gives you two skill upgrades and some cash. Put those 2 skill points into your merc discount and buy yourself a top tier bodyguard... shop around, look at the stats and see whos going to cause the most damage.

Don't stress about manning the outpost, like a dodgy pyramid scheme the funds from the second outpost are going to flow back to manning the first. Buy the cheap guys, they will be fine. This outpost will provide an additional upgrade which is going on the final merc discount which will make these bargain mercs even cheaper.

As you move around the outpost from this point keep upgrading bodyguard slots and hiring top tier guards, them summon those buggers at every outpost, between them smashing the place up and you spamming fire shield and bombing the cluster everyone is on fire, poisoned, and being shot with arrows or pummelled depending on your mercs.

After this follow your upgrades as they suit. I didn't worry too much about the rally skill instead getting the Intel on outpost, then max health, then maxing placing bombs on the gate for the last fort which pushes your troops through the fort causing chaos.

Restock on the fallen bodies whenever you see them.

When you enter the last room for the finale, bomb the hell out of the orcs on the stairs then get to work on the main while your brother mops up the stragglers. If your bodyguards are keen to party I assume they'll be of use though I didn't find it necessary.

Bombing the orcs on the stairs gives you a combo execution. The main is damaged and scared of executions which creates a stun lock so just beat him, execute, beat, execute, QTE and congrats!

Good luck!!!