Unlock Characters
Get the following characters by completing the missions indicated with the rating indicated:

Mission Rating Character Unlocked 
1 Professional Male Vampire 
1 Slayer Female Vampire 
2 Professional Zombie Skeleton 
3 Professional Zombie Demon 
3 Slayer Tara 
4 Professional Bat Beast 
4 Slayer Zombie Devil 
5 Professional Materani 
6 Professional Psycho Patient 
6 Slayer Sid the Dummy 
7 Professional S&M Slave 
7 Slayer S&M Mistress 
8 Professional Faith 
9 Professional Zombie Soldier 
9 Slayer Kakistos 
10 Professional Abominator 
10 Slayer Chainz 
11 Professional Zombie Gorilla 
12 Professional Joss Whedon 
12 Slayer Chris 

Get More Stuff
Finish these missions to get the item indicated:

Mission # to Finish Reward 
1 Anthony Stewart Head Interview 
2 Amber Benson Interview 
3 Nicholas Brendan Interview 
4 Robin Sachs Interview 
5 Chaos Bleeds Comic Book 
6 James Marsters Voice Over Session 
7 Anthony Stewart Head Voice Over Session 
8 Amber Benson Voice Over Session 
9 Nicholas Brendon Voice Over Session 
10 Robin Sachs Voice Over Session 
11 Joss Whedon Voice Over Session 
12 Out-Takes

Get Cemetary Arena
Finish Level 2 with a Slayer Rank

Get Initiative Arena
Finish Level 8 with a Slayer Rank

Get Quarry Arena
Finish Level 11 with a Slayer Rank