Divergence Boink! was a project I worked on a few quarters ago where I was making a fake digital text book about alternate timelines. It was fun to do, there was a lot of really cool stuff but the project was ultimately a flop, my fault more than that of the collaborators. I didn’t know enough Flash to make it work well and the program I used was still lackluster.

Basically though, moderator and musicsmith Squid (he does Homestuck musics) inquired about where history is different.
The first big change is that atom bomb and what it does. Still used on the Japanese to force their surrender the nuclear explosions caused a release of energy from a previously sealed dimensional pocket. This energy caused the development of the first super powered beings. The first official superhero was Mister Fearless.
Mister Fearless as previously mentioned, was able to project his personal fears into the eyes of his opponents. The problem was that he had a large number of illogical fears so when projecting dozens of kittens into the eyes of a bank robber, it did nothing to prevent him from being shot several times.
Before his untimely death though, Mister Fearless had inspired other early heroes including the original The Capitalist, AmeriMan, Habadasher and Apple Fly. These heroes after the death of Mister Fearless formed the American Justice Squad in 1952. The squad served to fight the few early superpowered people, evil scientists, common criminals and large amounts of Nazis who were ironically inspired to return to their evil ways by there being superheroes. The American Justice Squad began to swell in membership though it often was seen as an illegal organization based on the secrecy of identities and the general nature of vigilante actions. Despite the illegal actions, the American public happily cheered on the heroes who fought the good fight against evil without expecting anything. Then four years later, disaster struck as AmeriMan was gunned down by police in an accident.