Millenium Wrecker Walkthrough:

This map not that hard to beat.

You just have to like fighting Walkers and Furies!  ;)

Set up your forces and get ready, the first wave of 
Furies is on the way and will attack from the South West.
I kept the Factory at the North Geyser and the
Armory at the South Geyser, since the Armory is easily
replaced and the BDog Factory isn't.Tell your heavy units, 
(Tanks, Rocket Tanks) to guard the Armory and the 
Minelayers to lay mines at the sloped entrance to the 
quarry you're in.  I put the Recycler at the East
Geyser since it's the best protected by the Quarry walls.
Fight off the Furies and you'll have some scrap for the 
Scavs to gather.  

Repair and upgrade your units as needed, BDog Grizzly's 
are more effective if you add one more SP Stabber to them.

Turrets, Turrets, and more Turrets are good, since the 
terrain is sloped and it's hard to build Power Supplies and
Gun Towers.  You should quickly upgrade and repair after 
each attack wave, as the Walkers are on the way!

It's an uphill fight for a while, until you destroy enough
Walkers to get a breather.  There are many different approaches
to fighting Furies and Walkers.

If you like slugging it out go for Grizzly's and Bombers.
If you hate Walkers and Furies use Howitzers, (lots of them)
and take the enemy out from a distance.

There are plenty of Alien Bolt Mines around, so watch your 
step.  You'll have to take them out since your AI units
aren't very good at it.

The main Walker Factory is in the East, Central area and should
be a main target.

There are many side 'rooms' to explore, you'll have to hunt
down any stray Furies that got away.  One room in the NE corner
has many empty units the Furies were studying, as well as an 
empty Fury Walker!  (They must have run out of bodies!)

There's a FACTORY at the bottom of the pit in the center of the 
map that must be destroyed for the mission to be successful.
The easiest way to kill it is to take a Howitzer to the end of
the ramp and target the Factory.

As always, you're at the mercy of the games' Arificial Intelligence.
Sometimes the attackers are relentless, and other times you won't
encounter much resistance at all.  That's out of my control.