Here is the full list of all 16 Final Exam achievements worth 400 gamerscore.
You have completed an online multiplayer game!
You have completed a mission in 2 player local game mode!
You have completed all the missions in the game in "Rock Hard" mode!
You got the gold in every mission!
You healed a character on the ground 10 times in multiplayer mode!
You have completed all the missions in the game!
You won the golden glove on one mission!
You scored 300,000 points in a single game!
You've found all the weapons!
You launched the 4 special skills specific to one character in a single mission!
You killed 500 monsters with the chainsaw!
You killed 300 monsters with fire!
You've achieved a 50,000 point combo!
You've killed 1,000 monsters!
You exterminated 3 hordes!
You've achieved a 10,000 point combo!