Here is the full list of all 20 MEGALOMANIAC achievements.
Expand an operation globally
Monopolise an industry
Monopolise everything
Pester your way to the top
Turn scandal to your advantage
Improve your returns
Enter into politics
Further your political sway
Nothing can stop you now!
Successfully destroy a scandal
Purchase a solid gold suit
Upgrade your bonce
Upgrade your face with plastic surgery
See the world as it really is!
Oh dear
Not bad
Live fast die young!
You owned it all and killed the planet!
Lose your head
Foolish humans