First game: Ryan was truly an idealist who selflessly wanted to create a peaceful and happy objectivist society, and actually he did succeed. He was only corrupted by being forced to counter the actions of a criminal mastermind posing as "the people's hero", abandoning his principles and becoming ruthless and cruel, and this is what led to the downfall of him and Rapture. He's a tragic figure, while his enemy "Atlas" is just evil:

On September 12, 1958, Fontaine was apparently killed in a shootout with Ryan's men. His death was faked, allowing Fontaine to escape punishment for his crimes, and giving Ryan and Rapture false hope that their enemy was dead. Fontaine reemerged as "Atlas", proletariat hero. Atlas charmed the masses pretending to be a humble freedom fighter, handing out supplies to the poor and telling the disillusioned what they wanted to hear.