Played (and own) Digital Devil Saga. One of the best RPGs I've played in a long, long time, though the difficulty at some points is unreasonably high :?
Digital Devil Saga 2 is gonna come out soon, and there's only two new characters, so it's more of a continuation...but only one of the two will join, and it's based on choices you made in the first one.
The battle system is...interesting. Every person and monsters gets one action. If you get a critical hit or use something the enemy is weak against, you get an additional action as well as a chance to "frighten" the monster (gives a high chance they do nothing on their turn), thought limitted to one additional action per character. If you miss, use something the monster is strong/immune to, or heal the monster, you lose an additional action...this also applies to the monsters attacking you. Several skills consume HP instead of MP, though that's no a big deal since heal spells restore quite a bit for almost no MP (your characters start with 90ish hp/mp, the first heal spell restores about 70hp for 3mp...so yehh..)
Game has quite a bit of unique features (mainly the monsters, and the way the general plot is), only real downsides are..
-Enemy can ambush you, but you can't ambush them.
-Most of the stronger skills/abilities take a rediculously long time to get, but (luckily?) aren't even needed to beat the game.
-Most enemies get VERY high-level skills early on in the game, giving you a severe disadvantage (some monster near the beginning of the game get a 70% all-party charm...); while this could be considered tough, I personally find it to be a bit crappy to hafto fight 3 monsters with a 70%-success all-party charm attack.
Asides the difficulty, I'd say it's a GREAT game, even if it's a little shorter than one would hope =\
Oh, and one monster is a blue human-rhino thing with a head that detatches and tries to eat you. I think that in itself makes the game <3~
