PHp register

[Pain]

I have a simple register script and some weird things are happening. If i leave blank password or repeat_password then code is still executed. Why? I can't seem to find any mistakes in the code. (only when username is empty then i get "You need to fill everything").

<?php
$submit = $_POST['submit'];
$username = strip_tags($_POST['username']);
$password = md5(strip_tags($_POST['password']));
$repeat_password = md5(strip_tags($_POST['repeat_password']));

require("connect.php");

if ($submit)
{
if (!empty($username) && !empty($password) && !empty($repeat_password))
{
mysql_query("INSERT INTO users2 VALUES ('', '$username', '$password', '1000', '0', '0','', '', '')");
echo "You are registered <br />Your username is "."<b>$username</b>"."<br /> You may now <a href='index.php'> login </a>";
}
else
{
echo "You have not filled everything.";	
}
}
?>

[Pain]

I figured out