As the game title itself emphasizes, moral choices regarding sacrifice is Soul Sacrifice. Magic is not cast with spells or mana, but with sacrifices. You have two sets of three different kinds of magic that are constantly available to you to fight with, but every time you cast it, you must make an offering. Meaning if you run out of offerings, you're out of magic.
Fret not, there were health points in the map that allowed you to refresh your offerings. In the demo, there was only one map with no traveling required. All monsters spawned out of thin air and there was no searching required.
The game has a single player campaign, but the multiplayer mode was up for demo at the Tokyo Game Show. A co-op action battle game with up to four people at once, the objective is to defeat all monsters in the map.
Players, however, have a choice of either saving the monster (magically) or sacrificing them. The former choice will heal and increase your armor, while the latter will refresh your offerings and increase your damage. This also seems to apply to the boss monsters as they were formerly human.
The negative emotions that they had in their previous lives seem to have cursed and changed their form. In fact, while fighting the boss monster, you can experience their cries of agony and pain. The boss monster I fought kept crying about her last boyfriend (whom she ate).
Apparently in the full game, the cries of the monsters will start to reveal a bigger story altogether. I didn't have the opportunity to read them with the non-stop barrage of monster attacks and blood flying onto the screen obscuring my vision. After defeating the boss monster, your team will have the option of either saving or sacrificing it for different bonuses. Unfortunately, it is a voting system, and my team chose to save her.
Within the kinds of magic, there were already around 30 different kinds of spells which the player can choose from. A gun that shoots your blood, traps that unleash lightning bolts, area-of-effect healing spells, summoning spells, and the list goes on. My personal favorite was the lightning trap, with its absurd range of activation making you doubt whether its a trap or a homing missile. Every so often, players will randomly have the option of using what they call the suicide spell, which will allow you to cast a powerful magic at the cost of, well.. you.
After casting the spell, the player will have significantly lower health and a debuff for that boss round. One of the suicide spells was turning into a human torch, and everyone loves human torches.
Another interesting choice is whether to save your co-op friend or not. When another player is down, you have the option of either reviving him by giving you half of your current health or sacrificing him to cast a devastating spell. When you pick option B, your ally will die permanently, becoming a ghost for that round. You can, as a ghost, stare at monsters and lower their attributes. Or just watch your killer get overwhelmed by monsters as they fight without you.
The wide variety of spells available make it fun and refreshing, while the moral choice system seems to even change the type of boss you will fight to keep you playing even after you've finished once. I wouldn't define it as revolutionary, but playing with three other friends (that you don't mind sacrificing in-game) will make it a good addition to the Vita's library.