I had a really good time with this game, and I'd quite heartily recommend it.
If this has wet your appetite and you feel you want more, you should try Demon Gaze (same studio), or the Elminage series (competing company).

It has been a while since I played, so all the details aren't fresh in my mind, but without further ado...

It's an unashamed old-school grid-based blobber, with many little modern conveniences.
And it's not a particularly hard one at that.

You have a party of 6 people, and you run around on a variety of dungeons, fighting enemies, collecting loot and beating the snot out of bosses so you can collect McGuffins to advance the plot and get special abilities.

There are 4 ways to run into monsters.

1. Random encounters as you run around the level (the rate is fairly low, unless you use Force Alarm)
   
2. Pre-determined spots in a map (these respawn every ingame day, and have orange (regular) or red (boss) markers on the tile)
   
3. Checkpoints
   
4. Ambushing

Ambushing is done in certain spots of each dungeon, each ambush attempt has a greator morale cost (5, 20, 35, 50, etc), and toughter enemies. You use these same morale points to invoke special abilities you unlock with the same mcGuffins.
In each ambush attempt, up to 6 groups can pass by and each that passes increases the chance that they'll get first strike by 20% - this is very dangerous so you should avoid passing on the groups early on.
Each group generally consists of a tougher mini-boss monster and some weak cannon fodder to act as meatshields for the boss. These mini-bosses escape after several turns and take the loot with them.
Ambushing is your main source of equipment and loot in general in the dungeons, and the best way to fight enemies in quick succession if you want to grind levels.

As for combat, your party of 6 is divided into a front row and a back row; the first triplet in front, the second in back.
There is a lot they don't explain about combat, eg that you can use a whistle ahead of time (it'll light up the whistle icon at the bottom) to prevent bosses from screwing up your party order once. The spell casting UI also completely sucks, I had to google how to get to my wizard's attack spells.
You issue the actions you want your party to take, and then they're "applied" either normally or fast. Several prompts show up for each action, under normal mode, you advance 1 prompt per press of a button (you can also hold it), under fast mode it'll just skip through all the prompts rapidly. After a while I found myself just quickly tapping through and relying more on sounds and the simple animations to tell me what is going on over actually reading the prompts.
However once you reach the mid game, you'll tend to just stack up +Hit and +Avoid (you can see the current values on the portraits on the top right), and pair it with Force Guard so that enemies don't dispel them to their originals levels, and there isn't much strategy left.

The one thing I don't like about combat, is just how heavily levels factor into it.
For example, if your character is level 15, and a monster attacks and it does 200 damage (just about a OHK), but you can barely hit him and do pitifully little damage. But if you level up but with no real change in equipment or stats, he now hits you for considerably less and you can do a reasonable level of damage to him.
Combat does have a fairly strategic layer to it, and you do have a lot of tools at your disposal (and you unlock more and more over time).
If you can overcome the level gap, the main game isn't hard at all.

Dungeon design leaves a bit to be desired.
I do wish they could've added a bit more in the line of puzzles, but I suppose not every game can be like Etrian Odyssey.
Every dungeon has its own unique theme and feel, and usually a unique gimmick as well.
As a few simple examples

• Mausoleum of Sand: features many pits you can fall through
  
• Mausoleum of Forest: Features spinners that make it hard to know where you're going
  
• Mausoleum of Fire: Has "lava" tiles that hurt you if you step on them.
  
• Mausoleum of Sea: Spells are sealed away, and there are pusher tiles to simulate currents.

The story is fairly rudimentary and serves more as an excuse to progress from dungeon to dungeon. The characters are likeable enough and there's more than enough dialogue and exposition to allow you to get attached to the characters.
I have heard that the developer will be doing significantly more writing in future titles, I for one hope they don't because there is really nothing wrong with this level.
A lot of the dialogue is also voiced, and with Japanese voice work to boot (that's a big plus for me).

Also the translation is absolutely awful, not that I expected better from anything published by NISA, but shame on you all the same.
The best parts look and feel like a fairly literal translation taken out of google and tidied up a bit for grammar, and the worst parts are either incomprehensible or completely misleading.
The last bit plagues a great many useful items and skills!

For example, you can carry Dolls with you to save you from insta-kill attacks.
Some of them contain this in their description: Item loss rate UP.
Nearly everyone would think: "oh, I'm going to lose items if I carry this with me, oh dear!"
What that property actually means, is that there's a very good chance that the item won't break after saving you from disaster.

The character system is fairly simple and rudimentary.
Most of the depth comes from your class selections, and then your selection of cross-class skills.
I do like how your characters' ages factors into your survivability.
I also like that your reserves slowly level up and make some money for you.

As most know, there are 2 distinct art styles available, which affects the portraits of the characters you meet, and the CG scenes you get to look at during crucial moments of the plot.
First is the Type A art style by Yoko Tsukamoto, this is a more realistic/gothic art style, and despite some of the scenes looking rushed and incomplete, it's just oozing soul, personality, and atmosphere.
Second is the Type B by En Okishiji, it's banal boring generic animu moe blob rubbish; Okishiji is clearly a talented individual, but his artwork is a terrible fit for the game, and is in general just soulless, bland, and sorely lacking in details.

There is no mincing words about how bad Type B is, using it is like watching anime with dubs; if you want to do that, all the more power to you, but I just want you to know you have absolutely awful taste.

As for how lacking in detail type B is, just go look at Rui's portraits as an easy example.
In Type A, you'll notice several very distinct and unique features, such as her eyes looking like a lizard's. This detail (that is actually very important to her character) is completely absent in the type B art.

The locations themselves aren't that great, the models are low poly and the textures are fuzzy, but do keep in mind that this game was also targeted at the Vita.
The music is also fairly decent, it's never going make it into my top 100, but it never got on my nerves while playing.