It's available on the 3DS right now, BTW. There is also a cell phone-version, I believe (not sure if this is localized), but the 3DS version is the upgraded version and has more content, so you would be wiser to choose the 3DS version.
BTW, same company that made Adventure Bar Story.
To put it simply, there is nothing unique about this. Nothing particularly stands out.
However, it is generally all-around average, with nothing that particularly stands out as bad. The biggest attraction of this game is, of course, the price. For $5 (I didn't check the localized price, but it's probably around that), you can play this game. While there is nothing special about it, it will still last you as long as a normal RPG goes. At the least, you will get more than you paid out of this game.
So if you have time on your hands or just want to play a harmless RPG, this is a good choice. Also, Mercenaries Saga 2 is also available on the 3DS. I have not played that yet, but I'm pretty sure everything I said goes for that too.
So yeah, here are some characteristics of the game.
The game uses the grid-height type of battle system. Characters can only climb areas that are within the character's jumping range. Attacks from above, from the side, and from the back do more damage and have more accuracy than simply attacking from the front.
Also, it is turn-based, so the player gets to move all of his units first before the enemy does.
Characters have Power and Magic, Physical Defense and Magic Defense, Accuracy and Evasion. They also have resistance to elements, a percentage that they will block an attack and reduce damage done (equipping a shield is necessary), and critical hit ratio.
Characters gain EXP from attacking enemies and using skills on characters.
You can generally choose up to 6 characters to enter battle, but you have no limitations, which is actually kinda rare. So you can choose not to include the Protagonist in the party.
Overall, I felt the balance was fine. It definitely isn't really a walk in the park, that's for sure.
The only "problem" I saw was that you are not really told your opponent's attack range. You can see where they can move, but you cannot see the range of their attacks. That said, you technically can tell from their appearance.
On your first playthrough, "Normal" is the highest difficulty you can play. Once you beat it once, you unlock Hard and Intense and "Easy" becomes unplayable. You bring along various equipment, money, and Skill Points (used to gain skills and level them up), so there is no problem there either.
Between each stage, you are allowed to prepare before the next battle.
Options, Help, Save, Load, Items, Shop. You can also do Free Battles and grind all you want if you get stuck.
On your 2nd playthrough (I think you have to do Hard or above), you unlock a few EX stages in the Free Battle option. Unlike normal Free Battle stages, you don't just get a bunch of enemies on the map. There may be something special, like only 3 enemies, but those enemies are really strong. There is even an EX stage that allows you to use ALL 10 of your characters. Also, enemies on EX stages may drop unique equipment only found there.
Throughout the game and available from the shop, you can buy items that have special traits on them. By using money, you can combine these weapons together to add one of these traits (there are limitations) from one weapon to another. This is totally endgame stuff though, but you can make powerful, customized weapons through this.
Throughout the game, you will get up to 10 characters, though there are two character slots that can be one character or another, depending on your answer to a question of where you plan to fight. There are 4 male and 4 female characters that cannot be missed, but the other two slots are both a choice between a female and a male. As you can see in this case, I chose the route for the female character for both cases.
And finally, the Class System in this game. It is, as you can see, the game uses branches for class selection. When changing to a class for the first time, you have to use SP, but once you change into a class once, you can switch around for free as much as you want. You can also gain skills from every class you have been too, not just the one you currently are in. So eventually and ideally and endgame-ish, you would change a character to every class once before settling down on a specific class, depending on the stat bonus you like and equipment usable. Since you can use Free Battle, you can get as much SP as you want, if you are willing to invest the time.