If you had been paying attention, you'd have realized it plays nothing like the PSP games. Defense mechanics have changed from parrying to barriers, and the chase mechanic has been completely removed. (cont.)
Furthermore, the EX system has changed completely. Rather than having a meter, there are now EX Skills, which are 3 slots that reactivate over the course of time. There's a primary EX skill unique to the character, and two secondary skill slots that can be customized. (cont.)
Lastly, the "supers" in the game - EX Bursts - are completely removed in favor of a shared summon system. As opposed to EX cores, there are now summon crystals you must break in order to help fill the summon gauge. Once the summon is activated, your party gets specific permanent buffs along with specific passive buffs while the summoned monster itself attacks.