for each form element you wish to remove, you will need to remove the code for the server validation and the spry validation.
for example, if you remove the Contact_Name form element, you will need to delete the following line from the top of the page:
$WAFV_Errors .= WAValidateRQ(((isset($_POST["Contact_Name"]))?$_POST["Contact_Name"]:"") . "",true,1);
and this line from near the bottom:
var sprytextfield1 = new Spry.Widget.ValidationTextField("sprytextfield1", "none", {validateOn:["blur"]});