Cannot pass ‘S’ parameter more than two letters

You should use get_query_var instead of $_GET["s"], this is a built-in wordpress function that retrieves public query variables which would have already been parsed and fed into WP_Query.

$args = array("posts_per_page" => get_option("posts_per_page"), "post_type" => "astro_game", "paged" => get_query_var("paged"), "s" => get_query_var("s");

Reference: WordPress_Query_Vars