Yeah it's a straightforward real time combat system. You basically combine regular attacks with skills to try and "break" enemies (basically stagger them) which allows you to perform lengthy combos, keep the going for long enough and you can "boost strike" them, killing them regardless of how much HP they have left. You can also evade attacks and are encouraged to try and evade at the last second as it allows you to counter attack (which usually instantly staggers most enemies).
Here's an early combat encounter:
The main problem, as I mentioned, is that during boss battles the whole "break, perform combos and boos strike" gets thrown out of the window, and it turns more into a game of hitting a bullet sponge and evading attacks for 10 minutes.
Also once you have a full party and characters start getting better skills it can REALLY flashy in terms of visuals, to the point it's hard to tell what's going on.
Playing it at night is like: