Oh, I think we have to distinguish between two different complications here. One is aimed at the player. He has to collect a certain number of points, choose between different paths, some of which make entire events impossible, etc. That's not what I mean, and to be honest I hate it when Renpy games go overboard on this point, because I want to play through a game and see as much content as possible. In my opinion, the best RenPy games are those that give the illusion of player choice, but ultimately follow a predetermined story.That's not really the case, though. The storylines are fairly (and sometimes annoyingly) intertwined, to the point where dropping one can permanently stop others. E.g. blocking Ellie/Dylan early prevents Sophia/Dylan and consequently also Dylan/Emma as well as most of Dylan's interactions with other girls. Sophia similarly won't be able to get closer to Amber's son if she doesn't follow Aiden's storyline, etc.
What I'm talking about are compications in the story. These can have both a delaying and an accelerating effect on the course of the game, but can work completely without player decisions. One possibility was, as I indicated, for example at the Sam event with Sophia where attention was drawn to the window. The window made it possible for someone else to watch the two of them, which could then have been used by that character to make progress themselves. Here there are no decisions to be made by the player and therefore no branching, and yet it makes the game more interesting because the development accelerates and there are conflicts to solve.