What good games do you know of that were like a mini game in an actual game or were a small part of another game which got made into a small standalone game?
i think
Geometry Wars - Retro Evolved and
Portal are pretty good games. Geometry Wars originally was a minigame that was accessible through your garage in Project Gotham Racing on XBox 360. Portal is a game based on the Prey version of the portal gun i believe.
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