Grand Theft Auto 3 was not the first open-world game, but it laid a blueprint that the industry is, in many ways, still following to this day. Urban environments at the scale of Liberty City were practically unheard of when GTA 3 hit PS2, but Rockstar North – then known as DMA Design – managed to squeeze it all inside some impressively tiny memory constraints. Now, a dev has rewritten the game's source code to demonstrate how it all works.
The PS2 has just 32MB of memory to work with, and according to Mark Brown, the game journalist turned YouTuber turned game dev behind Game Maker's Toolkit, the assets that make up GTA 3's Liberty City constitute around 130MB of data. The devs split the city into three different islands, which each load separately, but even the opening island of Portland still features somewhere in the neighborhood of 40MB-50MB of assets.
