The Abandoned Lab is easily the most dramatic level of the game's first chapter. Zero infiltrates an old Wily base on his quest to reunite with his creator, fighting through guard robots and using Mag Flies to carry himself through gauntlets of spikes, ultimately ending in a battle against a super-powerful Doc Robot.
Being able to team up with Duo and take down Trio, the Evil Robot from Mega Man 8. The two heroes manage to make short work of him together in a free-floating battle in Tier X, Duo helping Zero by shielding him from Trio's strongest attacks and breaking Trio's shields in the end and Zero giving Trio everything he's got in his arsenal.
