Basic Trope: The heroes can't stop an evil plan until the final stage.
Straight: Emperor Evulz is attempting to gather the components of the Forgotten Superweapon so he can Take Over the World. Try as they might, Hiro and his friends can't stop him from gaining the components.
Exaggerated: Emperor Evulz has a complicated 100-stage plan, and Hiro and company fail at thwarting steps 1 through 99.
Downplayed: Hiro can defeat Evulz roughly 3/4 into the main story progress, and there's an appropriate game ending if you do so. However, you can only get the True Endings if you defeat him in the final stage.
The Emperor's plan has failsafes...until the last stage, that is.
The plan is complicated and rather solid, so it isn't until Hiro gets information on what the plan actually is that he knows how to stop it.
Stage one being completed is how Hiro learns of Emperor Evulz's plan.
Inverted: Hiro's gang wins the day by stopping the Emperor from gaining the weapon's components, but he revealed he had a backup plan - they're unable to stop him from taking over the world.
Subverted: Hiro's team has no problem thwarting stage one...
Double Subverted: ...but the Emperor reveals a second half to stage one, which they can't thwart.
Parodied: The good guys just sit back and let the Emperor get the components, knowing they won't be able to do anything about it.
Averted: Hiro and his crew thwart stage one, and the Emperor is defeated.
Enforced: A writer needs to set up some drama for the second and third acts. Besides, the story would be really short, otherwise.
Lampshaded: "You fools! You dare oppose me? It's still early in the game - I'm supposed to be winning!"
Invoked: Evulz knows Hiro will fail during the first phase of his plan, so he tries to conserve his energy until the final phases, in which Hiro will surely come back with more determination than ever.