There is no MC transformation, but pretty much every female in the game (excepting the eponymous and already-transformed neighbors) has a transformation progression where they get increasingly thicc as they're corrupted. (There is an option to leave a few of the ladies petite, but not all.) Regardless, I wouldn't consider the transformations "subtle".
(And as an aside, I too wish the tags were slightly more granular WRT whether transformation happens
to the player character or is caused by the player character. Same for games involving Mind Control.)