Your thoughts on this piece of writing?

[ I'm a fiction writer and i'm trying to write a very descriptive story regarding a serial killer called Jiyong, i just wanted some critizism on my dialouge and i wanted to know if its any good; I'm only 14 by the way, but dont expect something cute and fluffy that will just make you sick to the stomach. This is somewhat gory, so bear that in mind whist reading. ooh, its fanfiction by the way and this is the first chapter. ]

"Mommy! Mommy!" The boy cried out, tears falling from the corners of his tiny eyes as he watched the man pick up the metal knife; Jiyong let out a crooked smile as the boy cried for his mother, he loved it when his victims would sob-- especially when they were related, it made him feel somewhat accomplished inside once he heard people cry in misery. "What a loud boy you've got there" he chuckled, turning his brown eyes to look at the youth. The boy shriveled his body together like a jacket potato that had been cooked too much as Jiyong twiddled the knife on his fore finger, staring him down intently. "Don't you dare touch him with your dirty hands!" The mother yelled, trying her best to capture the killer's attention. Ignoring her, Jiyong continued moving closer to the youth, trailing his finger along the edge of the blade with a killer's intention; "He's got your eyes" he smiled bitterly and lifted the boy's face up with his index finger, "The same shade of sleek dark brown, almost mahogany with the color of the room reflecting off them.. Beautiful; Makes me just want to.." he stopped and let out a low chuckle, "...gouge them out with my bare hands"

Scared, sad and confused the boy still wept out tears, despite his red, swollen eyes, while the mother let out the world's loudest scream. This annoyed Jiyong immensely as he immediately leapt up and pressed the knife against the mother's soft, creamy skin, her messy dark hair falling along her shoulders. "What was your name again? Luna?" he asked, whispering the words into her ears. "..Y-Yoona" she spat out through gritted teeth, looking down on Jiyong like he was the scum in the situation. "Ah-yes, that sounds right-- so, Ms Yoona.... Shut your fucking mouth before i rip out your voice box.. .before the neighbors hear." he said the last part slowly, like she couldn't speak Korean properly. She had no choice but to be quiet, because she knew more than well that Jiyong wasn't kidding when he said something like that; so she nodded in obedience as she squeezed her eyes shut-- trying to stop the river of tears that was threatening to break through.

"W-what are you going to d-do to m-me?" the boy stuttered, trying to inch away from Jiyong as he moved closer to him. "Oh don't worry, young child-- it only hurts for about 2 seconds.." with that, he pierced the knife into the boy's lower abdomen, the blood rushing out of the body like a beautiful river of crisp, velvet red onto the white carpet of the small family's apartment. Yoona screamed her heart out, even louder than before, but this time the tears streamed down her dirty cheeks almost as fast as the blood; Jiyong growled and jumped over to the female, circulating his muscular hands over her thin neck as hard as he could. "I TOLD YOU, NO-FUCKING-SCREAMING" He screamed the words in her face before removing his hand and slitting her throat with the same blade. The blood from the female rushed down his arm as the other punched her flat in the jaw, multiple times-- what can I say? He hated screaming.

She didn't have near enough time to yell for help before her slender body was lying limp on the floor, as dead as the younger corpse beside her; standing up and wiping the blade clean on a piece of fabric torn from the woman's skirt he smirked to himself triumphantly, proud of his new kill. He bent down into the woman's handbag and stole her wallet and phone, before pausing and lifting her left eye lid open with his pinky-finger, "God, she really did have nice eyes" resisting the urge to gauge them out, he licked his lips, put the knife and stolen goods into his duffle bag and stalked out of the apartment-- as careful as ever, being sure to not let a single passer-by or neighbour see his face in fear of them contacting the police.

"I did good this time" he chuckled and mumbled to himself in a low whisper, swinging the bag over his shoulder and putting his hands in his pockets; looking up at the apartment's window as he walked down the street, "I did very good"