Warhammer 40,000: Battlesector

Gained after completing Mission 20 - Tyrant of Baal. The achievement is not difficulty specific and can be completed on the initiate difficulty.

Additionally, this is the only mission that ends immediately upon completing the objective, regardless of how many enemies remain. So l, rather than fighting across numerous Thornbacks, gargoyles, primes, and genestealers amongst others, you can simply run up the middle of the map and try to quickly destroy the hive tyrant and its 3 hive guards. This can be accomplished by using either Predators or upgraded Land Speeders.