Grand Theft Auto 3 was not the first open-world game, but it helped set a pattern that games are still using today. When it arrived on PlayStation 2, a city as large and busy as Liberty City felt unusually ambitious. Rockstar North, still known then as DMA Design, had to make that world feel present while working inside very tight hardware limits.
A Big City, A Small Memory Budget
The PlayStation 2 had only 32MB of memory available. Mark Brown, the game journalist turned YouTuber turned game developer behind Game Maker's Toolkit, explains that the assets making up GTA 3's Liberty City add up to around 130MB of data. In simple terms, the whole city could not sit in memory at once.
Rockstar's answer was to divide Liberty City into three islands. That structure mattered for more than the story or map flow. It helped the game manage what it needed to keep ready, and what it could leave out until the player moved closer to another part of the city.
The Trick Was Meant To Stay Hidden
On paper, the idea sounds straightforward: keep only the nearby city data loaded, then swap in other pieces as the player travels. In play, though, the trick has to feel invisible. GTA 3 worked because players could drive through streets, turn corners, and cross busy areas without constantly being reminded that the console was juggling data in the background.
To show the process more clearly, Brown worked from GTA 3 source code, reworked parts of the program, and built a new executable. That modified version lets the memory trick become visible, turning something normally hidden into a clearer look at how Liberty City was being handled behind the scenes.
Avoiding The Pop-In Problem
The broad explanation leaves out a lot of hard problems. One obvious issue is pop-in. If new buildings, roads, or scenery simply appeared around the player, the illusion of a complete city would break quickly. Rockstar had to make the transitions feel smooth enough that most players would stay focused on driving, missions, and exploring.
One solution was to use lower-detail versions of assets. These simpler versions could represent parts of the city before the full-detail assets were needed. As the player got closer, the game could move toward richer detail. This kind of technique was not unknown in 2001, but GTA 3 used it as part of a larger system that made Liberty City feel far bigger than the PS2 memory limit suggested.
Brown's full video covers more of the behind-the-scenes challenges and is aimed at anyone curious about the technical makeup of a classic. The most interesting part is not that every method was brand new, but that Rockstar combined familiar tricks into a game that felt unusually bold for its time. Z-retro's view is simple: GTA 3 remains worth studying because its magic came from practical limits, smart design, and careful illusion working together.
