Creepers

Code       Level    Difficulty
------------------------------
steveisdog   1       Easy
plkndzrtvk   2       Easy
tynzxprfsj   3       Easy
kwfrtftcsp   4       Easy
pylnvxzszh   5       Easy
kjhdslwcbd   6       Easy
hgkndcpbcx   7       Easy
plmknjjpmt   8       Easy
psfwlkcnmw   9       Easy
snccghwpgx  10       Easy
yyrqqmnvzk  11       Easy
pyrthzdhsl  12       Easy
fmnrxtkslh  13       Easy
fcblghpwrt  14       Easy
cbstphqfcz  15       Easy
fdndbslzcx  16       Easy
lllvlstkcm  17       Easy
lrsyzqpydn  18       Easy