I think the main story is worse than the original game and I was sitting there thinking "How stupid is everybody in this game?" constantly. To play the second game, you don't really need to have played the first one prior. There are a few returning characters, but they only briefly mention the previous game. There is however an included DLC post-game story that ties directly to the original game/story/characters slightly. I haven't beat that and I'm not sure I will because the gameplay became quite tedious towards the end of the game and this new post-game story area is even worse.
Anyways, in the first Demon Gaze you could create your own party. It was a nice aspect that let you customize how you play through the game. Unfortunately the second game does not have character creation at all really. You choose the looks for the main character as well as his alignment (which directly effects skills you learn as you level). Party members? They're demons you subjugate throughout the game. Each have their own skills attached to them, some of which may be different than some of the others that are of the same "type". The biggest issue I have with this isn't so much that they did this, but that all of the demons you subjugate start at god damned level 1 except for three. It's absolutely ridiculous that you're forced to grind to level them up to be even remotely close to your parties level. For that reason I've stuck with the party members you first obtain. Sure they get extra experience per battle, but it's still a pain in the ass that I don't want to have to deal with.
If you go through on the default difficulty, you can use the first party members you gain, but if you're going through on something higher, then you'll want to swap out for some of the newer demons. Particularly the caster at the very least. Like previous Experience DRPGs, you've got points where you can use gems to obtain equipment. You'll need to buy those gems from the shop in-game, so you won't be able to break down a bunch of stuff if you're playing the Vita version. Why does the platform matter? Because there's a bug on the PS4 version where you get a stupid amount of money from some/most battles compared to what you're supposed to get. It doesn't really make you overpowered, but it does reduce the need to grind for money to purchase gems and rooms.
Like other more recent Vita DRPGs you've got the touchy-feely (molestation) mechanic in this game that I'm not a fan of. It's pretty dumb and straight forward, but obtaining gems to max everybody out would be a massive pain. You can get the gems from beating recruitable demons as well as rare random battle drops. Otherwise you'll need to assign them to a room and give them a suitable piece of decor and then proceed to grind battles in hopes that their affection rating towards you increases. Outside of your main party, it's a pretty grindy gameplay mechanic be told. Despite not really liking the mechanic, there are a few "dates" or events that are tied to various party members from this that are fairly amusing.
Earlier I mentioned that the gameplay became quite tedious in the post-game DLC area. This is because you have to raise the difficulty up from the default just to even play it. Then you have a lot of enemies that reduce a party members health down to 1 HP. That's a mechanic I absolutely abhor as it cheapens the difficulty and turns it into a show where all you do is use Full Cure constantly so people don't die. There's no real strategy to to it. Plus one of the two bosses has a metric ton of health. I fought them once and after 15 minutes and only taking them down maybe 10 to 15% in health, I just turned the game off. I did not want to be part of a battle of attrition to see what ran out first, my items of the bosses health. The side boss is probably easier, but I didn't bother fighting them.
Inventory management is also a pain in the ass in this game too. They like to have a dozen of most item types that do the same thing but have different names. This means that each unique name is using up an inventory space and the game likes to give them to you in droves. If they combined the items down to a single name, this would not really be much of an issue. I just don't like going to storage and stuffing damn near everything in there after a dungeon excursion.
Also, if you remember the Mushroom/Skull quest from the first game, it's back as well. This time however its been slightly improved. After battles you can sometimes obtain map fragments that show where hidden items/chests are in the dungeons. I obtained most of them without any real grinding and managed to fully complete both those sidequests without any guide. Plus hidden doors can be found by using a demon that has a passive skill which locates them as well. The first demon you obtain will have this skill, as will some others.
In the end the game was alright, but I certainly enjoyed the first Demon Gaze a lot more. I feel like the switch to recruting demons with the touch-feely gameplay shit that so many other Japanese DRPGs are doing these days, kind of degrades the presentation in my view. If they hadn't made nearly all the recruited demons start at level 1 and gain a fraction of the experience the main party does, then I don't think I'd be so impartial to the game in general. I really hate having to grind up new characters just because others weren't available at the time which were objectively better. So I can't recommend the game, but I also don't think it's particularly bad outside of a couple really poor gameplay choices.
P.S. Magic in this game seems to suck. Never found any use for offensive spells.