Kolakoski

Score: 60.18 (pass)

#!perl
s/.?/$ARGV[$-[0]%2]x($&||1)/ge until/.{$ARGV[2]}/;print$&,$/

Score: 61.25 (pass)

#!perl -l
print map$x=(@x=(@x,@ARGV[($_&1)x--$x,--$_%2]))[$_],1..pop