Yeah Baten Kaitos is really unique. If you'll excuse me going on a bender:
It takes a bit to get going, but the simple mechanics are this:
- You attack and defend using cards, which you build in a deck
Cards have numbers, doing things like 123 or 333 in your attack or defensive attacks give you damage bonusses.
You have to block attacks with cards in the enemy turn to negate damage.
The beauty is that enemies really hit like a truck, so if you don't use defense-cards at all you'll generally be one-shot. You can use attack-cards for defence sometimes (like a sword-card) but they are far less effective than a shield-card for example.
It gets more interesting with elements, as everything 'stacks'. So say you cast Fire-Water-Water-Wind against an enemy (and let's say they all do 20 damage). The enemy is resistant to Wind, and takes only 50% damage from it.
That means you do 30 damage.
Because: 20+20-20 (since water negates fire) = 20
20+10=30
Consequently, if you're attacked by a move that deals 200 dark-damage, and you block with 200 physical, you literally wasted those cards since all the damage goes through.
It makes for some tough calls.
This is upped by the class-system. At the start you can only play 4(?) cards and only have a hand of 4. Each time you go up a class-level, your hand and playable cards go up by 1, but the timer you have to play your hand decreases in length. At first its infinite, to help beginning players. At max it's 2.5 seconds to make your choices.
The game has a great difficulty curve for this, and later cards will have 4 numbers on it, meaning you have to also not just choose the card, but also which number you use (you have to select the number using the c-stick).
Example of a random non-spoiler boss:
https://youtu.be/E7Rejym5xEw?t=53The beauty is that you can't rely on standbys, you have to think on your feet. A healing item is a card, so you gotta save it. And you might have to construct a number-combo on the fly. Note that the damage-values are significant. Doing a full 1-2-3-4-5-6-7-8-9 combo gives a 360% damage bonus.
IMPORTANT NOTE: the game is infamous for having one of the best plot-twists in the genre. If you care about that sort of thing, I highly recommend avoiding topics or spoilers about the game if possible. Personally speaking the twist was so impactful that I dropped the game for a few days to process it, and I still think about it to this day. It's really good.