If You complete the indicated task You'll get the allotted gamerscore.
Ned's Undead, Baby (49) - Killed Ned. Again.
House of the Ned (25) - Complete the "House of the Ned" mission
Jakobs Fodder (25) - Complete the "Jakobs Fodder" mission
Braaaaaaaaaaaaains! (25) - Complete the "Braaaaaaaaaaaaains!" mission
Night of the Living Ned (1) - Killed Ned...sort of