Factorial

Score: 49.11 (pass)

Just a simple tiebreaker improvement...

#!perl -l
($z=$z*$_%1e9)=~s^0*$^^for++$z..pop;print$z%10

Score: 49.12 (pass)

#!perl -l
($z=$z*$_%1e9)=~s/0*$//for++$z..pop;print$z%10

Score: 50.12 (pass)

#!perl -l
$z=$z*++$y%1e7,s/0*$//for($z=1)x pop;print$z%10

Score: 55.10 (pass)

#!perl -l
$_=substr$_*=++$c,s/0*$//-7for($_=1)x pop;print chop

Score: 60.13 (pass)

#!perl -l
$_*=++$c,s/0*$//,s/.*(.{6})$/$1/for($_=1)x pop;print chop