It's certainly a start! Make sure that plant pot and stall on the left aren't defying gravity, though. I'd also give the floor some texture, too - draw it as a grid, as if it's tiled or paved.
Also, think of things you might see lying around in a mall - posters on the wall, vending machines, public phones, signs and adverts, even trash if it's that kind of mall!
Making a "people spawner" is an interesting idea, but remember there's a limit on the number of objects/characters you can have in a room, so it probably wouldn't be quite as crowded as that scene in TWEWY. If you don't mind not having conversations with them, you can make them objects (which, in my opionion, would simplify it a whole lot), but you'd still have to draw walking views for all of the people.