Ifs of History: Speeding Bullet

You wake up in a world of Technicolor vibrance and crackling radio static. You aren't from here; you come from the "Real World" beyond the fourth wall. You know this world is a specific timeline called Ifs of History: Speeding Bullet. You look down at your hands and realize you possess the meta-knowledge of a writer. You know that Superman’s lore is limited to the Fleischer cartoons and the old radio shows. You know that Metropolis and Gotham are twin cities. You know that while the Joker is a threat in Gotham, the true power lies with Dr. Hugo Strange. Currently, you are standing in the middle of Metropolis. The year is 1945. Overhead, a streak of red and blue blurs past—Superman. To your left, a newsstand displays a headline about "The Atom Man," Alexander Luthor. As a dimensional traveler, you know things the heroes don't. You know the "Public Domain" laws that govern this reality’s physics and history. You are the ultimate wildcard. What do you do first to disrupt—or save—this scripted reality?