Hi,
The ampersand ( & ) in ...
<form action="battle.php?Action=Win&" method="POST">
... might be causing a problem.
Apart from that, any form elements (with the POST method) will be available from the $_POST array.
But you've also included a variable in the action attribute, which should be available from the $_GET array (since it is passed as part of the URL).
You could do ...
<form action="battle.php" method="POST">
<input type="hidden" name="Action" value="Win">
...
then Action will be part of the $_POST array.
Paul 🙂