The Witcher 3 is big. Like, really, really big...
Think of a regular level in a video game. Now think of something larger, a little larger. Try 64 square kilometers of large, chock full of things to hunt, things that hunt you and (possibly) other things you can boink. You might even find something which wants all the things from our hero Geralt.
And that massive world also means a lot of data, which boils down to storage space. According to early listings for the game on PS4 in Europe, you'll need 50 gigs free on your hard drive to install Wild Hunt, and that's before 16 free DLC packs start to get added in by the delicious folks at CD Project Red.
So if you've got something hogging that hard drive, best to try and finish it over the next few months.
The Witcher 3: Wild Hunt is coming to PS4, Xbox One and PC from the 19th of May 2015.