That's true. But you can look at specific trophies to narrow down the users who actually engage but then still "walk out of your story" (a ratio which of course

That's true. But you can look at specific trophies to narrow down the users who actually engage but then still "walk out of your story" (a ratio which of course varies largely from game to game). Spiderman, one of the high-profile games of PlayStation, has a trophy for each of its 3 Acts of the story. While 67% of the players finished Act#1, only 49% actually finished Act#3. So setting completion of Act#1 as a minimum to measure engagement, 27% of those who "sat down" still walked out before the end. And that is not a sign of failure but a landmark success of that industry. That's quite unique for a product of creativity. And even more odd: it doesn't even mean that those 27% disliked your product. They might even buy your next creation...