The creative pressures and arguments that have coloured Final Fantasy XV's development are most evident in the second half, where it almost switches geenre, away from the open world desidn of the The Witcher 3, which was an influence on the current team, to a much more traditional linear series of cutscenes and dungeons. Late in the game, a network of cramped corridors, stockrooms and baffling barracks feels like a hangover from another game entirely. Here, Noctis, working alone, must duck into doorways in order to hide from the stalking, haunted guards. The stealth is delivered in a horror style, complete with jump scares, a disembodied, Joker-like voiceover, and Resident Evil-style key-card puzzles."
To make clear the distinction between the two halves of the game, if you want to return to the open-world area you'll need to travel 'back in time' when at a save point. Once there, you can mop up any unresolved side-missions, until you're ready to return to the present.