It's easy to assume that when you compare it to a beast like GTA V that clocks in at 60gb, but keep in mind that Fallout 4 doesn't have a lot of needless civilian dialogue to take up more than 10gb alone and it doesn't have three different protagonists with several gigabytes worth of speech data. Now some people might assume that the game only being 28gb means it's tiny or that Bethesda gimped on the content.