How do players progress in grand theft auto iv s single player campaign?

The campaign takes place in the fictional Liberty City, modelled after New York City, and is presented from a third‑person perspective. Players control Niko Bellic, an Eastern European war veteran, and explore the city’s four boroughs and neighbouring state of Alderney. Progression is driven by undertaking narrative missions that move the storyline forward, allowing Niko to interact with key characters and confront the criminal forces affecting his past. As missions are completed, the plot unfolds across the different boroughs, giving players new areas to explore and additional narrative beats to experience. The open‑world setting lets players roam freely between missions, but the main progression is tied to the completion of these story‑driven objectives.