I unlocked this in level A-4, you basically drive a wraith around the whole level. Pretty short and sweet. I used Skulls Hollow, and Famine. Level takes less then 5 minutes and like I said you roll around in a wraith the whole time. If your tank starts getting low on health, there are numerous empty wraiths around this level for you to swap into.
Once you finish the objective, you need to get to the northern most part of the map, get out of the wraith then the level finishes, and the cheevo unlocks.