The Map Pack 2 Add-on for Sanctum has 8 achievements.
This is a secret achievement, can you unlock it?
Survive all the waves on Invasion.
Survive all the waves on Chasm.
Survive all the waves on Corporation.
Survive all the waves on Corporation on Insane difficulty.
Survive all the waves on Invasion on Insane difficulty.
Survive all the waves on Chasm on Insane difficulty.