The last level of the game will be a return to The Maw
Since the second game turned out to be a prequel, it would make sense for this to be a true sequel; and since this game appears to involve hopping around wildly different environments through mirrors, what better way to show it's a sequel then seeing what has happened to The Maw? Depending on how much time has passed, we'll either see rotting food and the decaying bodies of all the guests, or the entire structure would be falling apart/flooded and all the guests/staff would only have their skeletons remaining.The Carnival level will involve the kids playing some games
The trailers did show that there would be a carnival/circus/funfair/ect. level in the game, so it would be fun if to progress we had to play some games based around the kids powers. (Shooting gallery/balloon popping for Low, and Wack-a-mole/strength test for Alone)Low's going to get a bad ending.
There is a trend in Little Nightmares where protagonists either die or see themselves live long enough to become the villain (Raincoat and RK die, Six becomes just like The Guests and The Lady by committing cannibalism and taking The Lady's powers, Mono becomes the Thin Man) and they also have a tendency to contrast or be similar to the protagonist before them. And for Low, he has a lot of similarities to Mono that make me feel like he's not gonna survive the game, or at the very least, have a nice-ish ending. First off, this quote "Low is one of the few children who has never lost hope. He has lived in The Spiral for many years obsessed with reaching a mythical place, where he believes he will find a gateway leading home."' A child obsessed with a singular goal who never gives up, can use weapons, covers his face and has traveling-powers (mirrors). We saw how obsession tends to go in this universe and it never ends well. Plus, Low has powers, and people with powers aren't usually the good guys in the end. Not only that, but I wouldn't be surprised if Low's got similarities to monsters that we'll only spot with 20/20 hindsight like with Mono's hints.note
So all in all, Low is an obsessive child who's desperately trying to find a way home, believes in this mystical place, has powers and can fight. And in a game with the theme of Delusion I believe, and we've seen what happens to protagonists who follow the theme of the game, Low's probably super screwed.
The Necropolis is the Pale City many years later.
The first two games are set early on (or at least a few years in) to whatever Bizarro Apocalypse had taken place. In Little Nightmares II, we already see that the city was falling apart, their residents being twisted into freakish monsters while infrastructure collapses. III has us in a city, buried in rubble and sand, most likely many more years after the events of the first games. Odds are, the adults continued to mutate and become stranger and stranger until it became a free-for-all, The Monster Baby reaching the top of the food chain with its sheer size and medusa-like gaze. What few adults are left most likely mutated until they had become completely unrecognizable and fled, died or are hiding in other parts of the city.Six will be the Final Boss
The first game showed her killing and replacing the main antagonist, becoming a supernatural force of nature. The second game as a prequel showed how she had gotten to that point. Here, set farther in the future, we will see Six, having "grown up" into yet another monstrous adult, on the hunt for what few people remain. She had absorbed The Lady's abilities and she had a strong association with mirrors (broken ones in particular), and this game brings back mirrors as a motif, our protagonists traveling between locations through mirrors. Low will escape from the Nowhere, Alone will choose to stay
Interviews have made it clear that Low is the one searching for a way to escape the Nowhere while Alone is along for the ride. Since Alone is much more curious about the world they're in, it makes sense if the game's ending features the duo finding a way out only for Alone to choose to stay and keep exploring the Nowhere. Perhaps it is revealed that this is because the real world is not much better!