Complete each of the following achievements below to get the allotted gamerscore.
Unlockable Heroes for Lord of the Rings, The: The Battle for Middle-earth 2
Create a hero and give them the disguise and assassinate abilities (other abilities don't matter). Now train your custom hero and train a battalion of simple swordsmen and disguise your hero as one of them. The enemy will not attack your hero, so then you can assassinate the enemy hero that you choose.
As you might know, Thranduil is invisible all the time. But if enemy units or Fortress gets too close to him or he gets close them he will be uncoverd. First you want to kill wargs/trolls/wraiths/goblins with him, he doesn't kill buildings fast enough until level 7. Once you have the elven cloak, get into defense mode. Go into their base and pick off your enemies. When they get about a fortress length away click on elven cloak and don't attack anyone or move. You are now completely invisible. If they stay next to you, send a battalion of swordsmen to lead them off and pick a new location in the base. Buildings besides fortresses will not discover you so you're ok.
In Skirmish, while playing as any dark force, set the map for Isengard. Put yourself inside of the giant wall. If you build a lot of lumber mills all around in that area, you will gain resources constantly because of how many trees are there. I recommend 8-10 Lumber mills. This only works with Mordor, Isengard, and the Goblins.
In skirmish when you are playing with Men or Elves, instead of building a fortress at the start of the game, build: a couple of farms, (a baracks if you are elves), (an archery range if you are men), and an armory. Now upgrade the armory to level 3 and purchase all upgrades, including fire arrows at archery range when playing Men. Now construct two battalions of archers, and fully upgrade them. Then what ever direction the enemies are coming from, build a well and a hero monument right next to each other, and place your archers just in front of them so they are getting leadership from both the well and the hero monument. Now your archers will be indestructable because the well will auto-heal them, and the hero monument will give them +50% damage and armor, plus they will gain experience twice as fast accelerating them to level 5 in no time. Now the enemy will be crushed whenever they attack!