The techno freak, Barret:
Barret was called a techno freak in "Final Fantasy VII" by one of his known acquaintances, as he finally returned to his ruined mining town. North Corel had been destroyed by the Shinra in a set-up explosion. The citizens of North Corel looked for someone to blame and it all fell on Barret Wallace. Barret blamed himself as well. The current group (including the most popular Cloud Strife and Tifa Lockheart) are concerned for Barret (all the while finding out this information for the first time). We later learn in the story of "Final Fantasy 7" how Barret obtains the gun grafted into his arm.
We also learn why Barret's daughter is caucasian, as Barret is African-American. Finally, we also get the truth revealed of Dyne and Barret's friendship. All of this information, I will not spoil for you. If you are still interested, I highly suggest playing the game again.
Barret Wallace gameplay
Barret in battle is a charm to play. He is good in the back row because his attacks are ranged. Barret is one of the few characters that can hit enemies from far away (as well as close-ranged enemies). Being in the front or the back row determines damage. Since Barret uses the gun arm and shoots with most weapons, excluding the cannonball arm, he can do this. The back row is where Barret is best suited.
He has a large variety of weapons with different types of slots. He also has some interesting Limit Break techniques -- one of which that comes to my memory is the Mind Blow. This technique will lower an enemy's MP (Magic points) to zero. It is extremely useful in one of the hardest battles in not only the game, but the entire franchise.
If you use this attack vs. the Emerald weapon you might take it down a bit faster than normal!
Having a small lack of depth in battle design is common in "Final Fantasy VII." You can get creative with the characters' roles, but Barret Wallace is one of the difficult ones to do so with. Your best bet for an enjoyable approach is to ride out the story and enjoy some of Barret's fun and useful limit break techniques.