Dissidia Final Fantasy OO [Free] is the kind of game you can easily be sucked into for hours at a time if you like what it's giving you. Though loosely connected to the similarly named console fighting game, OO is as classic a Final Fantasy experience as we've seen on mobile, albeit one that has the usual free-to-play trappings and a selection of characters that spans decades of titles.
It's also somewhat unique in the sense that you can play for long stretches of time without investing a penny since there's no energy system. And there's no need to worry about grinding and hoping to get your favorite characters since you have the opportunity to recruit every one in the game to date just by completing quests.
That doesn't necessarily mean that you can stroll right through the whole thing, get all the best gear and max out your characters with no problem. Or at least, not without some guidance along the way, the kind we're happy to give.
The Basics -- Or, What is Bravery Anyway"
The combat system in Dissidia Final Fantasy OO is classic, turn-based RPG goodness. Both your characters and enemies act according to their speeds, and the order in which they attack is displayed in a bar at the bottom of the screen. When it's time for one of your characters to act, you can choose a target simply by tapping on it, then pick a BRV Attack, HP Attack or skill to use from the buttons on the right-hand side of the screen.

That BRV Attack is especially important. OO uses a system ca...