This guide will explain each mask and how to obtain them.
This mask is obtained by joining the Developer Group on Steam. The invite to it is obtained by being hired by Overkill Software. Once you are an employee, you also receive an invite to every mask group.
This mask is unlocked my doing something great in the PDTH Community. Something so great, that the developers see this and give you an invite to the Moderator Group on Steam.
Join the Vyse Group on Steam.
Complete every Non-DLC heist on the Overkill 145+ Difficulty unlocked at level 145. You will receive the “You are golden! Overkill salutes you!” achievement.
Record a video and upload it to social media. Complete overdrill on the Overkill 145+ Difficulty with all 4 players using the gold mask. Make sure the overdrill is 7,200 seconds (2 hours). To do so you will need either this mod: https://steamcommunity.com/groups/dahm4pd/discussions/3/364039785165189823/ or use the Beta Code: “duckandcover”. You must take all gold and escape with your whole team alive. It is forbidden to abuse glitches (i.e. camping in bags, camping under desk). Send the footage to the Owner or any Officer of the Secret group. They will review it and invite you or decline you. You will be notified upon invitation or declination.