I think you really want a hash-of-arrays (see perldoc perldsc):

use warnings;
use strict;

my $primaryFeatures = {
    'foo', ['fool', 'food', 'foot'],
    'bar', ['barricade'],
};

while (my ($key, $value) = each(%$primaryFeatures)){
   print "($key, $_)\n" for @{ $value };
}

__END__

(bar, barricade)
(foo, fool)
(foo, food)
(foo, foot)
[download]

I used square brackets to construct the arrays, then I dereferenced the arrays in the while loop.

It is also customary to use fat commas (=>) when constructing hashes

my $primaryFeatures = {
    foo => ['fool', 'food', 'foot'],
    bar => ['barricade'],
};
[download]