I often wondered why anyone would spend time on these silly things. But they're fun!

use strict; 
use warnings;
$_=[(25.5*6<<q{9}.1)=~m+(..)+go],//moss;
--$.for(1..((5<6).0));($/=>$.)=(-$.,$.);
$.*=@{_}=map{$.+=$/;$_+$.}grep{$_%2}@$_;
push@_,map{if(!int){$.+=$.}else{$.+=$/};
$_+$.}grep{($_+1)%2}@$_;die map{chr}@{_}
[eval join(q{,},2,1,4,3,0)]=>$/||\$\<<1;
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Update: With whitespace and comments: