Your idea seems to capture the spirit of the best suggestions in this thread well.

I was thinking a little more about it and came up with this::

use constant ATTACK_TYPES => [
    {
        type   => 'light',
        damage => 1,
        speed  => 5,
    },
    {
        type   => 'fast',
        damage => 1,
        speed  => 7,
    },
    {
        type   => 'heavy',
        damage => 2,
        speed  => 4,
    },
];

foreach my $attack ( @{ATTACK_TYPES()} ) {
    my $name = "new_$attack->{type}";
    {
        no strict 'refs';
        *{$name} = sub { return shift->new(%$attack) };
    }
}
[download]

Which seems too clever on the one hand, but on the other hand does a nice job of separating configuration data from code. The fact that it mostly eliminates the pitfalls of "Don't Repeat Yourself" is a bonus. But the real advantage is what can come next: The next logical step would be to store the attack types as a JSON file, and then process it like this:

use IO::All;
use JSON 'decode_json';

use constant ATTACK_PARAMS => [ qw/ type damage speed / ];

my $attack_types 
    = decode_json( io('attacks.json')->slurp );

foreach my $attack ( @$attack_types ) {

    exists $attack->{$_} or die "Malformed attack type: $_\n"
        for @{ATTACK_PARAMS()};

    my $name = "new_$attack->{type}";
    {
        no strict 'refs';
        *{$name} = sub { return shift->new(@{$attack}{ATTACK_PARAMS()}
+) };
    }

}
[download]

And now someone who doesn't care to learn a lot about programming could still manipulate the game's parameters without wasting your time.

Something like this has been done, though using ini files.

Although it's cool that such things can be done, I'm not likely to use it due risk of breakage that it introduces.