Here is the full list of all 20 The Complex achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Find the hidden ending
Get over 50% relationship status with everyone
Find an ending
Everyone dies
Sleeper agent
Sacrifices must be made
Rekindle an old flame
Find the evidence
He was alive...
Tell a joke
Reinforcements have arrived
Escort the investor out
Relationships matter