It’s been years since I played the first one, but I have spent a couple of hours with 2 now. My comparison is probably flawed since it’s been so long.
Battles are exactly the same, other than a lot better graphics. Not even little improvements like making it easier to select a unit behind another. Still the battles are fun, and aren’t always easy, though I haven’t lost a battle yet. Haven’t fought a boss either, though.
There is no longer a set map, but what appears to be random battles each time. You can choose between a lower, current, or higher level fight. There is a persisten boss battle on the map for level 6, but I am only level 5 so haven’t tried it yet.
Loot is rare now, which makes fully equipping your characters take much longer. You’re at the mercy to how much cash you can find and what shows up in the store.
Characters no longer gain individual levels, you now have a party level, so you don’t need to swap them out to keep them current. But equipping them and using a new skill purchasing system still means if you want to try out a new character, it will be behind everyone else unless you have money and extra skill points.
There’s 3 active skills per character and a ton of passive skills, which I haven’t used yet. Seems so far to be a step back from the old skill tree. It’s not as fun as leveling up a character like you did in the first one.
Anyway, it’s fun, especially after you get some skills and find characters you like. I would highly recommend it for someone who hasn’t played the first one. It is more of the same for people who were burnt out on the first one.