In order to defeat the commander, Duke must shoot and destroy his weak spot: his brain. However, it is protected by a reinforced metallic helmet which can only be opened by pressing the button near the creature. Unfortunately, the button is near the Commander's gaping maw, where the commander flicks his toungue around the button. By timing it right, Duke would be able to press the button and quickly jump up to the latform to shoot the brain until the protectve casing is clamped back on. It is also important that Duke must not stay on the top platfrorm, where the Commander's tendril's electrifies and this harm Duke. Repeat the strategy above until it goes into the ending clip, where the commander's brain explodes.