In many games there are entities whose existence in the gameworld is limited by time. These entities are removed automatically from the gameworld when their allotted lifespan is met. We call this expiration in order to differentiate it from removal (see Removal). Typical examples of entities that are expired include entities that convey temporal powers to the player and that are only available for a limited amount of time (power-ups), entities created by other entities (flames, bubbles, etc.), and entities that are no longer active in the world (corpses, debris).
Removal implies an effect due to the activity of a player, player controlled-entity or an agent. Removal does not account for entities that cease to exist in the gameworld by themselves. We call this expiration due to the gameworld.
In Dead Rising, the entire world (along with the player) expires after a certain length of time. This limit is imposed by the day/night cycle in the game world. The player has 72 game hours which are spent trying to further the story. The goal is that when the time limit expires, the player will have completed the necessary story elements to result in a victorious ending.
Yoshi's Island DS
In Yoshi's Island, Yoshi can turn into a mole-like digger that moves through and fits into places that Yoshi can't normally go. Yoshi must collide with a bubble that has the digger symbol to transform into the digger. Once he is in this new form there is a specific time amount until the digger expires and Yoshi transforms into his original self. To become the digger again he must reach another bubble with the digger symbol.
The dinosaurs of this game spit out bubbles to capture enemies and pop them to kill the enemies. However should the player never pop the bubbles they will expire after a period of time, either releasing whatever was captured, or simple bursting if they were empty.
Super Mario World
Super Mario World contains a number of puzzles which require the player to navigate platforms and other world entities within an alloted period of time. When the time expires, the entities are removed whether or not the player had yet reached the goal. In this example, we could argue that the gameworld has imposed a lifespan for all the entities in the world and when that time expires, they are removed.
Once a note has passes the ship's capture bar, it is either captured by the player, or immediately destroyed because it was missed. This is a strong example of expiration because if the note is not hit at the exact moment that it is to be hit, it is removed automatically from the game world. This is a weak example because we could argue that the notes don't actually expire, they just exist in an inaccesible part of the gameworld.