Barret is the second character that you are introduced to during a playthrough of the game. He is with the team for nearly the entire duration of the game with the exception of a small stint in the Corel Prison when Barret runs off from the party.
Barret is probably the second strongest character in the game. His Limit Breaks are fantastic, including his second Level 3 Limit Break, Angermax, which hits multiple enemies multiple times. His Ultimate Weapon, 
Missing Score, can also do an incredibly high amount of damage. Finally, Barret can be placed in the back row much of the time which will reduce the amount of damage that he takes.
He has high HP and Defense, but note that he has fairly weak Magic and Spirit stats, which means that he should be a physical attacker rather than a character that relies on Magic Materia or Summon Materia.
Barret is able to use the following weapons (Gun-arms):
Gatling Gun (Initial Weapon)
Assault Gun
Cannon Ball (Melee Weapon)
Atomic Scissors (Melee Weapon)
Heavy Vulcan
Chainsaw (Melee Weapon)
Microlaser
A·M Cannon
W Machine Gun
Drill Arm (Melee Weapon)
Solid Bazooka
Rocket Punch (Melee Weapon)
Enemy Launcher
Pile Banger (Melee Weapon)
Max Ray
Missing Score
Check out the Limit Break section for more information on Barret’s Limit Breaks.
