I was just about to purchase the new game, "The Witness", when I noticed that next to the title, it is listed as a PSN game. Does that mean PlayStation Network, or PlayStation Now? I recently purchased "Sportfriends" and to my surprise, it was required to have a Now subscription to play this game. This game also has the "PSN game" next to the title. Do you need a subscription to PS Now to play the witness? What exactly does that abbreviation mean?
It stands for PlayStation Network and it means that the game is specifically made for digital distribution and purchase only. So they're only available digitally. You initially won't find them in retail, unless it's some re-release or something like that. Like The Witness and Sportfriends, these are typically smaller games meant to be download-only. It -confusingly- has nothing to do with PlayStation Now.
PSN means to play the game you need to be connected to the internet and to be signed in to your PSN account. If you buy the full game, it doesn't require PSN and you can play offline.
Source is my personal experience, just tried to launch a PSN game without internet connection and can not. It keep asking me to sign-in to PSN.