Beat level 20.
Beat level 40.
Beat level 60.
Beat level 100.
Beat level 80.
Unlock Charlie Brown.
Unlock Lucy. (lvl 21)
Unlock Linus. (lvl 41)
Unlock Sally. (lvl 61)
Unlock Pigpen. (lvl 81)
Unlock Peppermint Patty. (level 101)