Kolakoski

Score: 67.19 (pass)

#!perl -l
$$=pop;s/.?/$ARGV[1&pos]x$&||$ARGV[0]/eg until/(.{$$})./;print$1

Score: 74.18 (pass)

#!perl -l
$c=pop;$_=join"",@ARGV;$|=0until~s/./$ARGV[$|--]x$&/eg&&/.{$c}/;print$&