The Dead Rise As Quel'thalas Falls Orc Tides of Darkness Mission 11
- Destroy Elven Stronghold
To start you'll want to focus entirely on building up your base and strengthening your defenses. Build a Guard Tower and Cannon Tower at the western entrance of your town as well as another Guard Tower and Cannon Tower along the tree line at the southern portion of your base.
Build up an army of Catapults, Troll Berserkers, Ogre Magi and some Death Knights - a new unit that you can make starting on this level. I'd also recommend, of course, building a Goblin Zeppelin and exploring the map so you know where everything is and what to watch out for.
The Elven Stronghold that we're tasked with destroying is found at the far southwestern portion of the map, surrounded by a frozen river and only accessible from narrow ice bridges. Compared to the last level this one is a piece of cake since we're given an insane amount of resources to work with. Almost the entire map is covered in trees - there's 0 chance you'll ever run out of lumber to harvest on this map.
As you explore the area around your base too you'll discover multiple gold mines which are guarded by four or five Alliance archers. Once you've made a small army of 10 or so troops you'll want to send them around the map clearing out all of the Alliance guarding these gold mines followed by Peons which will go to these areas and construct Great Halls.
When you clear the two nearby gold mines you'll find the last one that you can ravage all the way down at the southeastern most portion of the map. This is also a great spot to invade the enemy town from.
You have two options for raiding the enemy base... You can use Goblin Sappers sparingly and take out many of their defenses using them. Or you can lead a rag tag band of Catapults and Troll Berserkers/Ogre Magis into the town and do things that way. The Catapults and Ogre Magis will take a lot more skill and patience than the sappers will but they have much better odds of success.
The choice of strategy is up to you! If you destroy the entire town and the level doesn't auto complete for you it's likely because there are some enemy troops left alive somewhere around the map. Grab a pack of 10 or so units and roam around the map looking for the last few enemies to lay to waste.