The front-view combat system is designed so that the playable characters rely solely on equipping items (any item) for stats and skills rather than grinding for levels. You can also collect every undead mook you defeat and add them to your own stock of summonable mooks, which compensates a bit for the small party. Many of the skills share their name with skills from Standstill Girl, which was also made by Uta. The game also features a dungeon crawling movement system, where enemy symbol encounters can only move when the party moves, requiring careful movement on the player's part if they want to minimize encounters.
This game provides examples of:
- Alliance Meter: This example could be easily mistaken as a Karma Meter at first glance, but the conflict isn't nearly as black and white as it looks. There is a hidden variable starts at 0, decreases by 1 if you free a human slave, decreases by 3 if you kill an undead merchant near the end of a dungeon, and increases by 1 if you kill a human slave. Lower numbers indicate Jeannie's respect for human life while higher numbers have her prefer the undead as the true form of happiness. Going too far in either direction results in Jeannie taking her views to the extreme.
- Anti-Frustration Features:
- It's possible to break down items into their non-magic stone components, allowing the player to recover rare materials as long as they don't waste them with the wrong recipe.
- If you already tried fighting the secret boss before, later attempts allow you to skip the cutscene and go straight to the battle.
- Bittersweet Ending: The "kill humans" ending, the neutral ending, and the secret ending see both characters survive, but Marta was an undead all along and only the secret ending allows them to escape the kingdom. The kill humans ending is especially bitter due to Jeannie's FaceHeel Turn.
- Bonus Boss: It's possible to escape the kingdom from the lower sector and get the secret ending, but this requires the party to defeat Celaeno and Alcyone, a pair of powerful Pleiades Knights.
- Book-Ends: The path to the secret ending is behind a bombable door in the very first room of the game.
- Boring, but Practical: Placing a character in the back row prevents them from being targeted by most single-target skills, but also causes them to deal reduced damage if they have a close-range weapon equipped. Since Marta has the ability to summon minions, going for a pure long-range and back row setup is still usually worth it to keep the aggro on expendable minions.
- Contractual Boss Immunity: Averted. While bosses have reduced chances of being inflicted with certain statuses, the chance is never zero.
- Downer Ending: Despite how saving humans seems like the most altruistic choice, it'll result in the saddest possible ending, since it's the only ending where Marta dies, at Jeannie's hands no less. Worse yet, Jeannie's body starts to decay and she is resigned to never finding happiness.
- Earn Your Happy Ending: The secret ending is by far the happiest one for the siblings, since they get to be free outside the kingdom. However, this requires them to win a tough battle against the two Pleiades Knight elites, who are tougher than Queen Anastasia. The upside is that the ending doesn't have any kill or save requirements.
- Eye Scream: Marta's left eye appears to be stitched shut or slashed.
- Guide Dangit:
- Bombs are mainly used to destroy cracks in walls, but it's less obvious that they can work on the doors in the first room of the game. Additionally, there's no hint that bombs can also be used as temporary obstacles that enemies on the map have to walk around.
- Since the kill/save meter is invisible, it's impossible to tell what killing the undead merchants does without looking it up online or completing the game.
- Karma Houdini: Only in the secret ending, which doesn't involve fighting Queen Anastasia. This means she'll continue to rule over the kingdom and perpetuate her undead supremacist policies.
- Knight Templar: The Cadaver Queen is fanatical about sacrificing souls and humans to the Deathless Goddess, to the point where she tells Jeannie that she's blessed for becoming a voluntary sacrifice. She also considers Marta a heretic for trying to help Jeannie escape.
- Multiple Endings:
- Beating the Final Boss with the kill/save variable at -15 or less will result in Jeannie taking the throne in order to start an extermination campaign against all the undead, for the sake of humans. Worse yet, she starts by tearfully killing Marta, who was an undead all along.
- Winning with a kill/save variable of 15 or more will result in Jeannie taking the throne, but this time to kill all humans and turn them all into undead, under the reasoning that they'll be happier as immortals. Marta survives in this ending, but ends up becoming The Dragon to Jeannie.
- Failing to meet the above requirement will result in Marta advising Jeannie to go into the doors to heaven, but she refuses because she has blood on her hands and because she wants to remain with her brother. Jeannie becomes queen and is unsure about the future, but avoids being a Well-Intentioned Extremist like in the above routes.
- Beating the Bonus Boss will result in Jeannie and Marta successfully escaping the kingdom, though with the revelation that Jeannie intentionally got captured so that Morte would be forced to reunite with her in order to save her. Since the two are outside the kingdom, Marta is made into Jeannie's thrall to preserve his undead existence, albeit with his sentience intact.
- Nintendo Hard: While it's possible to farm souls to buy a limited number of LP and slot upgrades, it's impossible to power through this game with levels like in other RPGs, due to the lack of an experience system. Every boss is designed to have difficult gimmicks, to the point where ailment infliction on the later ones is almost mandatory.
- Well-Intentioned Extremist: Combined with He Who Fights Monsters. In the two kill/save endings, Jeannie will resort to genocide of either humans to grant them undeath or the undead to protect humans. In either case, her goals are more destructive than Queen Anastasia's, to the point where some NPCs in the "kill humans" ending compare her negatively to her predecessor.