Your second example, for me, seems to work just fine:

#!/usr/bin/perl -w

use strict;

use CGI qw[:all];

my @list = param(),"\n";

print @list;
[download]

When run like this:

% perl test 'this=is&a=big&test=ok'

Returns 'thisatest' as expected.

Note that your example used '(:all)' with out qw(), which doesn't seem to be correct.