The first-person dungeon crawler transformed for me once I was introduced to Shin Megami Tensei: Strange Journey on the Nintendo DS. Before SMT, my experience was with ruthlessly difficult titles such as Might and Magic and Wizardry, which were incredibly unfriendly starting points to the genre. Speaking of Wizardry, it is an extremely popular series in Japan, so much that the Japanese continued producing games long after the series was dead in the West.
Mary Skelter: Nightmares is thoroughly steeped in the elements of this genre which has been beaten like a dead horse and practically saturates the PS Vita, the platform it was originally ported from. And while it is derivative in just about every sense, and familiar to the bone, it does just enough different to set it apart as being somewhat unique.
Source: Destructoid Review: Mary Skelter: Nightmares