Although you'll find several distinctions between parts 1 and 2 in Alfred Moyes’ narrative poem "The Highwayman" (1906), I'll try to explore three in greater detail.

The first is the change in atmosphere: the mood shifts from moonlit romance in part 1 to realistic violence in part 2. Since “The Highwayman” is a tragic love ballad, this is a natural transition. The poem opens with the following lines, which emphasize elements from both gothic romance and fantasy.

The wind was a torrent of darkness among the gusty trees.
The moon was a ghostly galleon tossed upon cloudy seas.

Though there is an undercurrent of danger, actual peril is still only a faint possibility. Bess, the local innkeeper’s daughter, is waiting for her lover, the swashbuckling “highwayman” or robber, to ride up the road and meet her. As the highwayman comes up to Bess’s casement or window, he reaches up for her, and she lets down her hair so “a black cascade of perfume came tumbling over his breast.”

The highwayman promises Bess he is going away for a robbery but will be back to see her by moonlight the next night, even though “hell should bar the way.” His words prove prophetic and the poem’s intense romance begins to give way to stark reality. Tim, the ostler or stable-hand who also loves Bess, eavesdrops upon the lovers and reveals the highwayman's plans to “King George’s men."

In part 2, Tim’s betrayal bears immediate fruit, and Bess waits endlessly for the highwayman, watching the empty road. Thus, the mood shifts from Bess’s hopeful wait of part 1 to that of despondence. Soon, some people do appear on the road, but none of them is Bess's beloved.

A red-coat troop came marching—
Marching—marching—
King George’s men came marching, up to the old inn-door.

The men immediately launch the narrative into violence, tying up Bess at the foot of the bed and gagging and harassing her. They tie a musket or a rifle beneath her breast so she dare not move and wait silently for the highwayman to come up to the inn. However, Bess makes the ultimate sacrifice and warns the highwayman of the presence of the redcoats by freeing her hands enough to pull the trigger to the musket. The shot kills her but warns the highwayman, who turns back. But when the highwayman learns of Bess’ death as she sits “Bowed, with her head o’er the musket, drenched with her own blood,” he spurs back “like a madman” and is shot by the redcoats like a “dog” on the road. Thus, the moonlit romance of part 1 ends in the brutal realism of part 2, even though the epilogue concludes you can still hear the clip-clop of the highwayman’s horse on the road on certain beautiful nights.

The second distinction between the two parts is in the treatment of Bess, the landlord’s daughter. In part 1, she is treated gently, as befits a romantic heroine. She is described as “bonny,” or beautiful, plaiting a “dark red love knot” in her hair. The highwayman’s tone with her is tender and full of promise.

He rose upright in the stirrups. He scarce could reach her hand,
But she loosened her hair in the casement. His face burnt like a brand
As the black cascade of perfume came tumbling over his breast;
And he kissed its waves in the moonlight,
(O, sweet black waves in the moonlight!)
Then he tugged at his rein in the moonlight, and galloped away to the west.

However, in part 2, Bess is immediately subjected to harassment by the redcoats. Ironically, she is treated far better by the robber than she is by the keepers of the law, who tie her up and mock her, “stealing” kisses from her without her consent. The “dark-red” love knot of her hair begins to represent the red of bloodshed. Though Bess wins back some agency through her bravery, desperately working on her ties till she can maneuver one finger enough to reach the trigger, the poem ends in her shocking, graphic death.

Tlot-tlot, in the frosty silence! Tlot-tlot, in the echoing night!
Nearer he came and nearer. Her face was like a light.
Her eyes grew wide for a moment; she drew one last deep breath,
Then her finger moved in the moonlight,
Her musket shattered the moonlight,
Shattered her breast in the moonlight and warned him—with her death.

The third distinction is the change in imagery to denote the shift from the whimsical to the violent. This is best illustrated through the contrasting descriptions of the highwayman in the two parts. In part 1, the highwayman’s coat is “claret velvet,” a deep burgundy color. His breeches are “brown doe skin” and the road he rides on is a “purple ribbon” under the moonlight. Thus, the imagery associated with him befits a dashing, romantic hero. However, as he spurs back after hearing of Bess’ death in part 2, the highwayman is no longer a romantic hero but an avenging angel.

Back, he spurred like a madman, shrieking a curse to the sky,
With the white road smoking behind him and his rapier brandished high.
Blood red were his spurs in the golden noon; wine-red was his velvet coat;
When they shot him down on the highway,
Down like a dog on the highway,
And he lay in his blood on the highway, with a bunch of lace at his throat.

The purple road has turned “smoking white” while the highwayman’s spurs are “blood red.” The romance of the moonlit night has been replaced by the unforgiving light of the “golden noon.” The powerful adventurer of Bess’s real and imagined life is stripped of dignity, shot “down like a dog on the highway.”