This mission can be very frustrating especially if you're playing legal, it took me a while to beat him, or rather, to discover an effective way to. First off your opponent Unfettered has two backup MTs in each end of the complex who will constanly pick away at you, and being that he is using Plus enhancements he will almost always be airborne and above you if you don't stay on the move. His weapons include multi missiles which he will use if you get too far away from him so you should equip some type of missile interceptor extension(decoys may not work against AI properly), and the spread bazooka which can shower multiple rockets down upon you and raise your heat level quickly. He also has a chain gun of which he can fire in the air, tracking and overheating you if you stay still. He also has the moonlight laser blade which can take off a big chunk of AP if he gets a direct hit on you so don't get too close unless you are skilled at using a blade yourself and you see it as worth it. The best way I beat him was to use the BAL4 dual multi missles for back units, a core with a good Overboost like the XA/2 or the ROOK, the Karasawa with the OP-ACC optional part to speed up the gun's shots, also use the VAT reverse jointed legs or heavyweight legs. First off OB toward the first MT and let off a missile shot, quickly turn and head toward the other letting off another blast of missiles, these missiles will destroy these MTs in one shot each so after doing this you can now totally concentrate on taking on the AC. First let off around 6-7 volleys of missle shots up until the enemy starts hovering under the platforms that the MTs were on, when he either does this, lands or comes close to you or the ground switch to the gun and let off shot after shot, hitting him and disabling his mobility with the stun affect of the shots, this strategy should easily destroy him if you are good enough at keeping him in the lock box and you can move around good enough to keep him from getting behind you too much. Another strategy you can use is a quad with a grenade rifle and a laser cannon on back, maybe also a grenade launcher.
First off, this mission calls for a bit of ducking and shooting, equip the heavy quad legs, the MAC dual plasma back mounted cannons, and the weapon arm dual laser cannons. Use a head with good ranged radar and a core with a good efficient overboost like the ROOK or the XROO. In your AC you should have the optional parts that upgrade your energy weapon attack power, firing rate, and perhaps the capacitor expander. At the beginning of this mission you will see the flying enemy far off in front of you, first off you should get behind the first building in front of you, and if you want, you can position yourself so your back is up against the building. You should now look up, and wait for the massive MT to pass over,the trick is you only have to hit it's head and body, anything else is a mere waste of ammunition, and with the weapons you're working with you should take your shots carefully. After the MTs initial passing, you should hurredly OB to one of the taller building somewhere in the middle of the battlefield. Use this strategy of hiding behind and buildings and shooting the enemy as he passes over, and you should easily be able to complete it if you got this far. First off use the MAC cannons since they are the most powerful, and if all the MAC shots somehow don't connect with the head or body and you end up running out of the MAC shots, finish the job off with the arm cannons, you have more than enough firepower to do the job if you take the shots carefully.
In this mission you have a rematch with the Raven Zaltehook who you beat in the arena in the first duel in which he used the energy machinegun. Now it's different, the arena appearance has changed and you now have a much more unrestraned moving area, no obsticles in your way but with this comes consequence. The bad thing is that he has been given a handicap, meaning he'll be assisted in order to make his winning the match more of a possibility. Through this match there are constantly lasers picking away at you from the ceiling, though not too powerful shot for shot, the results of taking hits from the AC and these over time will eventually show vast drops in AP, so therefore the opponent should be killed off quickly. The best way I've found to do this is using a strategy similar to my first for fighting Unfettered, you equip a Karasawa, the dual multi missles, and the fast lock and good energy weapon part upgrades. Basically you shouldn't worry about assaulting the ceiling lasers(though I know it's tempting) Concentrate all your attention in side strafing, use a heavyweight, midweight, or heavy RJ, and let the missles fly whenever you can get a lock on the AC. If he shows himself blast away at him with all you have. You can also jump to the top ring platform and attack from there, you can often catch him stalled at top, barely moving. One thing though, just don't stand there and let the lasers hit, stay on the move, and keep the destruction of the AC on top priority.
Tank, 80 ammo fast small missle arms, black grenade launcher, 20% ammo increase, Good OB on Core, don't waste grenades... 'nuff said.