The map is packed with satirical takes on real-world landmarks, making it instantly recognizable: Liberty City (3D Universe) - GTA Wiki
This game is set in the same Liberty City as GTA IV , but viewed from a top-down perspective. It removes the heavy realism in favor of stylized, colorful graphics, but the street layout and boroughs are identical to the GTA IV map.
Colony Island (Rikers-style prison), Happiness Island (Statue of Happiness)