Seems a lot of people on this thread are unaware that Severus Snape not Malfoy kills Dumbledore. Btw According to Malfoy's mother when she visits Snape, she voices her suspicion that Voldemort only orders Malfoy to kill Dumbledore because he knows he will "fail" thereby giving him another reason to punish the Malfoy family
From the Half Blood Prince
"Harry tore past Hagrid and his opponent, took aim at Snape’s back, and yelled, “Stupefy!” He missed; the jet of red light soared past Snape’s head; Snape shouted, “Run, Draco!”and turned. Twenty yards apart, he and Harry looked at each other before raising their wands simultaneously. “Cruc —” But Snape parried the curse, knocking Harry backward off his feet before he could complete it; Harry rolled over and scrambled back up again as the huge Death Eater behind him yelled, “Incendio!” Harry heard an explosive bang and a dancing orange light spilled over all of them: Hagrid’s house was on fire. “Fang’s in there, yer evil —!” Hagrid bellowed. “Cruc —” yelled Harry for the second time, aiming for the figure ahead illuminated in the dancing firelight, but Snape blocked the spell again. Harry could see him sneering. “No Unforgivable Curses from you, Potter!” he shouted over the rushing of the flames, Hagrid’s yells, and the wild yelping of the trapped Fang. “You haven’t got the nerve or the ability —” “Incarc —”Harry roared, but Snape deflected the spell with an almost lazy flick of his arm. “Fight back!” Harry screamed at him. “Fight back, you cowardly —” “Coward, did you call me, Potter?” shouted Snape. “Your father would never attack me unless it was four on one, what would you call him, I wonder?” “Stupe —” “Blocked again and again and again until you learn to keep your mouth shut and your mind closed, Potter!” sneered Snape, deflecting the curse once more. “Now come!” he shouted at the huge Death Eater behind Harry. “It is time to be gone, before the Ministry turns up —” “Impedi —” But before he could finish this jinx, excruciating pain hit Harry; he keeled over in the grass. Someone was screaming, he would surely die of this agony, Snape was going to torture him to death or madness — “No!” roared Snape’s voice and the pain stopped as suddenly as it had started; Harry lay curled on the dark grass, clutching his wand and panting; somewhere overhead Snape was shouting, “Have you forgotten our orders? Potter belongs to the Dark Lord — we are to leave him! Go! Go!” And Harry felt the ground shudder under his face as the brother and sister and the enormous Death Eater obeyed, running toward the gates. Harry uttered an inarticulate yell of rage: In that instant, he cared not whether he lived or died. Pushing himself to his feet again, he staggered blindly toward Snape, the man he now hated as much as he hated Voldemort himself — “Sectum —!” Snape flicked his wand and the curse was repelled yet again; but Harry was mere feet away now and he could see Snape’s face clearly at last: He was no longer sneering or jeering; the blazing flames showed a face full of rage. Mustering all his powers of concentration, Harry thought, Levi — “No, Potter!” screamed Snape. There was a loud BANG and Harry was soaring backward, hitting the ground hard again, and this time his wand flew out of his hand. He could hear Hagrid yelling and Fang howling as Snape closed in and looked down on him where he lay, wandless and defenseless as Dumbledore had been. Snape’s pale face, illuminated by the flaming cabin, was suffused with hatred just as it had been before he had cursed Dumbledore. “You dare use my own spells against me, Potter? It was I who invented them — I, the HalfBlood Prince! And you’d turn my inventions on me, like your filthy father, would you? I don’t think so… no!” Harry had dived for his wand; Snape shot a hex at it and it flew feet away into the darkness and out of sight. “Kill me then,” panted Harry, who felt no fear at all, but only rage and contempt. “Kill me like you killed him, you coward —” “DON’T —” screamed Snape, and his face was suddenly demented, inhuman, as though he was in as much pain as the yelping, howling dog stuck in the burning house behind them —”CALL ME COWARD!”
Harry is clearly a Level1 magic user in this scene while Snape is probably Leveled up to 60
