Instructions
Dodge or roll to avoid the large objects Mezner hurls in your direction.
Absorb the electrical energy from the broken electric line that hangs above Mezner. Throw your glaive at one of the tentacles and use the "Hayden's Energy Pulse" ability to damage all three tentacles at the same time.
Continue charging your glaive and throwing it at the tentacles until they have all been destroyed. You will now be able to damage Mezner.
Throw your glaive at Mezner as soon as he tries to use his sonic power. This ability will kill you if you do not interrupt it. Use Hayden's "After Touch" ability to ensure the glaive finds its mark.
Destroy the tentacles that appear on the ground and then deal with the ones that have respawned on Mezner's main body. Mezner will attempt to use his sonic device again once you destroy the new tentacles.
Slam your glaive into Mezner with After Touch to deliver the killing blow and finish the game.