The base features a multi-elevation environment, which can benefit the player if soldiers are positioned at higher vantage than the enemy. Both layouts consist mostly of pathways with guardrails that serve as cover. They can easily be distinguished by the loading graphic, as one features an L-shape (see photo, right) while the other does not (see photo, above).

Upon launching the mission, the Alien Base appears to be randomly selected between two layouts. – Mission Objectives, XCOM: Enemy Unknown ▪ Identify and capture the base commander, if possible Use extreme caution analysis indicates the presence of a large combined enemy contingent. We have gained access to the Alien Base by means of the Skeleton Key. – Central Officer Bradford, XCOM: Enemy Unknown We've only got one chance to make this work though, so let's make sure we do it right. Vahlen's research, and some clever developments down in Engineering, this 'Skeleton Key' should allow you to breach the alien compound. It can then be initiated at any time from Mission Control. This mission becomes available after crafting the Skeleton Key from the Outsider Shard.

Xcom 2 base layout