Persona Q: Shadow of the Labyrinth employs a very unique art style compared to other games in the Persona franchise.
Atlus went for a “super-deformed art style” due to its connections to Etrian Odyssey. There’s also the fact that the 3DS’ screen is a bit on the small size.
Artist Shigenori Soejima explained to USGamer:
“There are two big reasons for the super-deformed art style. One being that, because this is a crossover with Etrian, which has always had that style, we wanted to keep that iconic look so that when people saw it they’d know, ‘Oh, this is similar to Etrian Odyssey.’ If it were in the regular-looking Persona style, especially on 3DS, people might be confused and wonder, ‘Is this a new Persona game, a new Etrian title?'”
“Secondly, on the 3DS, the screen is much smaller. My usual type of character designs… trying to squeeze them onto a tiny screen just wouldn’t look good. In order for my characters to shine, basically we had to scale them down.”