I'd certainly drop the && do { ... redo } hack which I find to be not even close to worth the "surprise" factor (plus the maintainance problems of not noticing when you forget a "redo"). And I'd add a different hack (single-argument for) which I think offers a big win in this specific case:

    for(  $self->{gamedescr}{Game}  ) {
        while(  ! m/\G\z/mgc  ) {
            if(  m/\G($REnumber)\s*/mgc  ) {
                my $num=$1;
#...
            } elsif(  m/\G($REanymove)\s*/mgc  ) { 
                push @{$self->{GameMoves}}, $1; 
                $color = $switchcolor{$color};
            } elsif(  m/\G($REcomment|$REeolcomment|$RERAV|$RENAG|$REe
+scape)\s*/mgc  ) {
#...
            } else {
                die "Invalid input...";
            }
        }
     }
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