A full digital download of Metal Gear Solid V: The Phantom Pain will require 25.1 GB of free space on PlayStation 4, according to the preorder listing on the Japanese PlayStation Store.

The Phantom Pain is a massive open-world game, so it’s expected to require a lot of space. But surprisingly, it takes up less than most other open-world games–less, in fact, than Metal Gear Solid 4: Guns of the Patriots on PlayStation 3. MGS 4’s PS Store listing has it at 26.6 GB.

Although publisher Konami hasn’t addressed the file size yet, some possible reasons for the game’s small size are that all of its cutscenes are real-time, it doesn’t have much audio (Snake won’t talk much, after all), or it simply has really good compression.

In comparison, The Witcher 3: Wild Hunt takes up 50 GB, Batman: Arkham Knight requires 45 GB, and Bloodborne is 25.3 GB.

If you’re interested in The Phantom Pain on PlayStation 3, that version requires only 11.7 GB.

Metal Gear Solid V: The Phantom Pain launches on September 1 for PS4, Xbox One, PS3, Xbox 360, and PC. Today series creator Hideo Kojima revealed that boots inspired by the game will go on sale soon. Additionally, if you buy certain Nvidia video cards, you’ll get the game for free on PC.