I changed the settings.pl to use regular key names instead of variables. If I want to interpret a file as perl code, I generally use an eval this way:

$ cat settings.pl 
%default_settings = (
    verbose => 1,
    debug => 0,
    help => 0,
    game => "etqw"
);

$ cat app.pl 
#!/usr/bin/perl -w
my $settings_file = "./settings.pl"; 
use strict;
my %default_settings = ();
open SETTINGS,$settings_file or die "cannot open $settings_file";
my @data = <SETTINGS>;
eval "@data";
close SETTINGS;

my %settings = %default_settings;
print $_,'->',$settings{$_},"\n" foreach (keys %settings);

$ ./app.pl 
verbose->1
game->etqw
debug->0
help->0
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This allows me to not 'require' anything at startup but rather gives me the flexibility to do what I need if I need it.