MAP20: WarTemple is the twentieth level of Icarus: Alien Vanguard. It is set in a simulation of a massive temple, notable for containing a reversed, upside-down version of the first third of the level as the second. It was designed by Rand Phares.
After using the western set of teleporters in the map's center (south of the yellow and blue door), you are in the map's northeastern part. From your teleport destination, go eastsoutheast, ascend the stairs next to the green armor, follow the walkway with the waterfall to your right and climb some more stairs to enter a room with a rocket launcher. While the southern wooden wall can be walked through, the eastern one in fact is a lift. Ride it up to an alcove (sector 308) with a chaingunner, a medikit and a backpack.
After using the eastern set of teleporters in the map's center, you are in the map's northwestern part. From your teleport destination, go westnorthwest and climb the narrow step west of the wide one on the main path to enter a room with a rocket launcher on a plinth. Similar to secret #1, the southern wooden wall can be walked through. Press on the western one and an elevator will lower nearby to reveal an alcove (sector 181) identical to the one in secret #1, with the same items, although these are located differently. Approach the grates to lower the elevator again, ride it up and drop onto the plinth to acquire the rocket launcher.
In the northwestern part of the map, from the rocket launcher's plinth mentioned in official secret #2, pass the northern door. Step on the southeastern upside-down crusher and ride it up. Jump over to the opening in the southeast to encounter an imp (and a chaingunner on medium and hard skills) and to find a box of rockets and a backpack.