The key to that is to design things in terms of ways that characters can change state and then have dynamic, responsive chains of states that lead to different places rather than pass/fail barriers.

HP like mechanics are a simple example of a general state graph like this (and it's what 4e tried to go with for it's skill challenges), but something like positioning has more traction with the world and is less abstract.

I'd probably go with factor sets - a scenario consists of a set of Factors that apply, and actions generally swap certain Factors for other Factors, and you're trying to navigate the composition of the set into a configuration that makes success possible.