Theresia (テレジア?), known in Japan as Theresia: Dear Emile, is a survival horror video game published by Aksys Games and developed by WorkJam, released exclusively for the Nintendo DS. It is one of the few DS games to received an ESRB rating of M for "Mature" and a CERO rating of C or "ages 15 and older". The game was released on September 11, 2008 in Japan and on October 30, 2008 in North America.
Theresia is a first-person perspective video game, consisting of two stories, each sharing a common background: an unnamed country, presumably under strict martial law by the time the game takes place, is engaged in a fierce and bloody war with an unspecified opposing nation. No further details are provided: the player is then thrust directly into the role of Emile, titular protagonist of the game, with which to venture into the first half of the story. Upon completion, a shorter second chapter with an unnamed protagonist is unlocked, providing a deeper insight into the overarching background narrative.
Throughout the course of the game, both characters have to explore their confinements, trying to escape and learn the details of their past, avoiding traps and coming face to face with personal demons and other psychological dilemmas along the way. The game made use of the Nintendo DS touch screen capabilities.
Source: Wikipedia, "Theresia: Dear Emile", available under the CC-BY-SA License.