I really liked it. It had a nice story with interesting characters and universe.
You have the first person view while exploring the dungeons, you can talk to demons and they still ask for your opinion/money/macca.
Macca here is extremely important, it's like oxygen for demons so if you have demons in your party (and you should obviously) well they'll eat more or less macca so you have to be careful about that. But you can collect them by talking to demons, exploring dungeons or exchanging them for money.
The tool for summoning demons here is a gun, and you can customize it with mods that can allow you to talk to demons during a full moon, recover hp while you walk..
You also have fusions (double and tri), sword-fusion and you can create a marionette. I didn't use that but it looks cool.
Also demons have natures : Some prefer magic attacks, physical, do whatever they want, heal...
There's a lot of things in this game that makes it a great SMT game. But it's kind of easy and short for a SMT game, but that's why it's perfect for newcomers