Each character uses a *whoring* stat to indicate the progression of the given character, but that's not the only flag that's important. Internally, characters also utilize progression stages that allow the writers to write coherent story, appropriate for your current progression.
Previously the game would advance without ever giving you the choice to play through all events, skipping content basically. We've thought of it as a bad design and instead, we've decided to give the player the ability to decide when you want to push the storyline further.
So my advice is to play through all events and press the level up button once you feel like you've had your fun with the current corruption step.