Generally in RPGs you have some sort of die roll to resolve actions and modifiers to that die roll, usually in the form of bonuses or penalties applied to the resulting number(s). Those modifiers vary quickly, from action to action. More often than not, they’re less important than the die roll itself, few modifiers are enough to ensure success or failure and most of the tension comes, not from the modifiers, but from the uncertainty of the die roll itself.
What about an approach wherein the modifiers, the build-up of advantage, was the thing that mattered, and the tension came from the time necessary to do so? For example, say a character has one chance at a task and, without any prep, it’s a 50/50 but each round spent preparing—whether testing an opponent’s defenses and dancing around or working painstakingly over the ship’s broken hyperdrive—increases the chance by 5%. So with 10 rounds of prep, the character will succeed, but will he have the time? What if his opponent lunges first and gets a lucky hit? What if the Empire’s star-fighters close in and destroy the ship before it can go to hyperspeed? Then it becomes a gamble: do you prepare this round or go for it? What about next round? How about now? What are you doing to improve your chances? Looks like you enemy is closing in, is 65% enough? How about 70%… and you go for it!
This is a somewhat different approach from the micromanaged, round-to-round action, such as: attack roll, defense roll, attack roll, defense roll, etc. or rolling an action, failing, rolling again, failing, then rolling a third time and getting lucky and succeeding. Rather than rolling the lesser actions, they’re just prep to the big gamble of the final action that decides it all.