Fallout 3 and Fallout: New Vegas both approached their end-game in a very similar way; once you hit the hard level cap that was the end of your character development (unless a new expansion arrived to bump it up) and once you completed the main story, there was no more adventuring in the wilderness. The credits rolled, and you were done.
Not so with Fallout 4. In a tweeted response to fan queries, Bethesda confirmed that the game will have no level cap, and will allow you to continue exploring once the story is complete.
“To our fans who’ve asked: Fallout 4 doesn’t end when the main story is over and there is no level cap. You can keep playing and leveling,” reads the tweet.
Which is good news, as long as Bethesda keeps an eye on the potential problem of over-levelling. I’m assuming there will be a series of DLC packs on the way after Fallout 4 drops this November 10, and it would be a shame if everything you encounter explodes into a million fragments under your godlike strength.