well here's how it works
See those tiles at the top right? you're in a constant war to secure those bonuses to make battles easier, you tap a card and it takes up one of the slots at the top right, your opponents are also constantly doing the same thing, it's all in real time so if you're not paying attention the enemy will scoop up all of the bonuses and you're in for a really tough time, getting your soldiers in those slots back to back gets you a combo though i haven't been able to tell what the advantages of that are
If you look closely at my cards to the right you can see how the tiles are lit up, that tells you where your attacks will hit, so that SSR at the bottom (which sadly isn't mine ;___
can attack in a straight line while my SR can attack the front 3 squares
there are skills as well and your skill gauge fills up over time allowing you to perform various skills like damage or healing
gatcha rates are as follows: SSR = 3 percent, upped to 7 percent if doing a 10 pull, SR = 13 percent, upped to 93 percent if doing a 10 pull, R = 84 percent, decreased to 0 percent if doing a 10 pull
i haven't been able to tell if it's P2W yet since i don't have a grasp on everything but from what i can tell it's fair like Chain Chronicle