Maybe if Terra Battle was a game you'd pay money for and you didn't have to gamble to get new characters, maybe if there were no stamina system, maybe if it didn't use the timed drag-your-characters-around method of control in puzzle games, maybe if it didn't do all these things, I would've liked it better. TB is a RPG where you move your characters around a battlefield to "pincer" enemies in order to attack them. You have a wide cast of skills and abilities that trigger and alter the grid and there is also a wide range of characters to collect. Ultimately, I didn't like it much.
I'm not a big fan of energy systems, nor am I a fan of having to randomly get characters whenever you pay basic (or premium) currencies. What I love about most 'real' RPGs is that your party is set and balanced, you can get different classes and party members along the way, but you'd never be able to pay to get a stronger one. That being said, you get a few premium bucks so you still have a chance to get SS-rarity characters and things like that. I had a mage that shot lightning bolts and decimated the enemy like no other of my characters could do. The character system is interesting since you have skills you learn by leveling-up your heroes and they can have multiple jobs (and equip skills from different jobs). A staple of some RPGs, but combined with the F2P scheme, it becomes uninteresting.
The way battles play is that you start on a grid with your party in a predetermined position and the enemies as well, then you move one character - during which time a time bar drains - in order to try and flank enemies. After you've moved one character, all of the enemies's timers go down, at 0 they do something. Either they move and attack if they flank you, or use a skill. The problem I have with this is how enemies all act but you only move one character at a time. You can move a character through another to push it the way you came from so you technically can move more than one, but some situations - corners and the like - prevent you from doing anything meaningful with that system. Why not being able to move all characters? And in that case, just move them without all that sliding non-sense. On most first turns, you can't do much, but the enemy will probably be able to attack you on their turn.
The music is pretty good and there is some merit to the battle system with it's chain and combos and field effects, but otherwise there isn't much in Terra Battle.