Time travel without paradoxes
If only it were that simple... However, the idea behind time travel in Steins;Gate is good enough to explain away most paradoxical situations.
Similar to the multiverse theory, whenever an event occurs, or does not, a world line is created. It's a simple premise, easy to understand, and the lack of complexity means you're able to focus more on the story than the science.
As with any show that deals with time travel, you either ignore the science and enjoy the show, or you look at the science and then complain about how it makes no sense... I'm looking at you Dr Who. But with the extremely limited length of time the main characters are able to travel, excluding Suzu, it means that you aren't having to remember too much, but also, you're not expecting to see huge changes; for example, Akihabara not being a moe town... yeah, that'd never happen.