Halo Wars Campaign Special Achievements

There are special achievements associated with each campaign level. Here are some things OmniscientDeath and I picked up on our playthroughs.

• Xbox 360 Achievements has a decent achievement guide posted
• Mission 1 Everything's Better with Bacon: This is hard because your Warthog gunner tends to kill grunts before you can splatter them. I recommend using the queue movement command. If you press and hold "X", your unit will go there after it's done with its current action. Send in one Warthog at a time and click "Y" on the Grunt as soon as its visible so the gunner stops shooting. Immediately (before your hog gets to the Grunt), queue up a Warthog move to retreat back out of range so that your Warthog automatically turns to come back as soon as possible and doesn't gun down any remaining Grunts. Do the same thing at Alpha Base, but be careful to position Forge and your Marines well out firing range. It took my 81 Grunts to get 50 splatters. Take your time.
• Mission 3 Coveneant "Hot Drop": You don't have to get all 5 kills at one time. If you don't get all 5 the first time, just turn the bridge back on and try again.
• Mission 4 The Real Winner: See the screengrab from Xbox Life. Open the console next to the black box and Adam should come running out.
• Mission 7 Micro Manager: You can get this by just hitting the Scarab with the MAC cannon, and not moving any of your units. The only caveat is that the Scarab will likely burn through the ruins and start hitting your base before you can get enough MAC blasts in. Spend your time building up resources. The Scarab will take out the closest turret and closest building before starting on your command center. Once those are gone, just keep building Supply Pads in the empty space, the Scarab will hit that one first before going back to your command center. It costs 100 resources every time and they go quick, so be sure to keep an eye on your MAC recharge time.
• Mission 10 The Procrastinator: Recommend building Scorpions and Wolverines to escort the Gremlins.
  
• Mission 12 Battened Down the Hatches: As soon as it starts, use all your resources to build Cyclops until you max your headcount. Don't forget about the two airlocks furthest from the power core. Be efficient, it takes almost exactly 4 minutes on easy if you are perfect
• Mission 15 Thinkin' About My Doorbell: Be careful, when you open a door, the glass panels fall away. Any ground units you have parked on them will die. Also, the doors will only if you have cleared all the aliens away from the control panel.