Mechs Stats:

Speed: 2. It actually hovers off the ground slightly for most of the fight, but it's really, really, really slow. More accurately, it has very poor acceleration and therefore maneuverability, though its top speed is actually quite high in comparison and floating makes it possible to strafe - though how useful this will be is questionable given the speed it will typically be moving at.
Melee: 3. Hiroki's mech lacks in traditional methods of dealing melee damage and is functionally missing a limb for it, but is surprisingly dexterous (due to the aforementioned floating) when engaged up close. The arm not occupied by her cannon, while not having any particular tricks, consists of an extremely powerful clawed hand that is specialized for catching and pinning opponents, and tearing pieces off of immobilized or very heavy ones. Additionally, the mech is quite heavy, lending it extra force should an opponent be crushed by it.
Firepower: 6. The mech's main cannon is incredibly powerful and the mech's powerplant is more than enough to match. Alongside this, it has auxiliary cannons mounted on the backs of the legs, and the "wings" are mostly an array of more guns and thrusters for control. Overall it's capable of firing an absurd number of low-powered bursts or concentrated, powerful beams. Some of the wing-mounted guns are slaved to the main gun, aiming and firing together with it. The leg guns essentially respond when Hiroki kicks. The main cannon can fire beams, bursts, or exploding packets of plasma, as well as creating a short ranged "plasma cutter" for melee.
Armor: 6. Heavy plating and strong joints allow the thing to physically take quite the beating, and the majority of the wing-mounted cannons are controlled by an internal targeting system for the purpose of point defense - attempting to shoot down incoming projectiles. The plating is also designed with energy dispersal in mind, able to take a number of energy-based attacks before failing. She's recently installed an emergency shielding system should any plating fail or be removed; such gaps will be filled by energy shielding that will explode outward should it be overwhelmed.
Signature Attack: None. Hiroki's strategy doesn't rely on a single finishing blow; rather she simply batters down her opponents with a withering barrage of superheated plasma.
Special Ability: Hellfire Burner. Hiroki's mech can overcharge its propulsion systems, suddenly launching itself in a chosen direction at high speed.