It's a huge bitch to TA. Be patient if you're just trying to beat it. Learn the attack pattern. When he's electrified and jumps up into the air, go all the way to one side and wait for the targeting reticle to stop moving and then do a homing attack away from the wall, then go all the way to the other side. You'll be able to see him shoot the arm but it'll be out of reach to hit you. Then run back to the boss, stopping a short distance from him, and wait for the claw arm to come back down. Homing attack it and you'll get at least 4 hits in on the boss (jump, hit, homing attack, repeat) per boss cycle. After he comes back he'll jump around. After you get some practice with this strat you can actually just stand in a certain place each time and he'll jump over you.
It simply gets trickier later on when he fires the pink bullets and the laser.