Good news for people who like long games, and I mean stupidly long - even The Witcher 3 (opens in new tab)'s own playtesters can't finish it in under 25 hours.
Now to be clear, this is CD Projekt Red's own internal testers. Nobody knows the game better than them. These are the people paid to touch every tree in the game with a different object for years at a time to see if anything breaks. They've lived and breathed nothing but The Witcher 3 more or less since there was something to play, and the fastest time they've managed is 25 hours the studio told GameReactor (opens in new tab). That's apparently "taking the best route and clicking through all the dialogues".
It means that even if you were rush through the whole thing like some sort of weird motorway safari park (look at the blurry lions!) you'd still be playing for one hell of a long time. However, if you want to play it properly then the recent talk is of the game having around 100+ hours of content if you were to do everything. Either way: not short. Long.