$query = "
            INSERT INTO users (
                username,
                password,
                salt,
                email,
                pokemon
            ) VALUES (
                :username,
                :password,
                :salt,
                :email,
                :pokemon
            )
        ";
        $query_params = array(
            ':username' => $_POST['username'],
            ':password' => $password,
            ':salt' => $salt,
            ':email' => $_POST['email'],
            ':pokemon' => $pokemon
        );
<form action="register.php" method="post">
            Username:
            <br />
            <input type="text" name="username" value="" autocomplete="off" data-lpignore="true" />
            <br />
            <br /> E-mail:
            <br />
            <input type="email" name="email" id="inputRegister" autocomplete="off" data-lpignore="true" />
            <br />
            <br /> Password:
            <br />
            <input type="password" name="password" value="" autocomplete="off" data-lpignore="true" />
            <br />
            <br />
            <p>Choose your starter Pokemon:</p>
            <input type="radio" name="pokemon" <?php if(isset($pokemon) && $pokemon=="Charmander") ?> >
            <img src="images/charmander.gif" />
            <p style="color:orange;">FIRE</p>
            <input type="radio" name="pokemon" <?php if(isset($pokemon) && $pokemon=="Bulbasaur") ?>>
            <img src="images/bulbasaur.gif" />
            <p style="color:green;line-height:13px;">GRASS</p>
            <p style="color:purple;">POISON</p>
            <input type="radio" name="pokemon" <?php if(isset($pokemon) && $pokemon=="Squirtle") ?>>
            <img src="images/squirtle.gif" />
            <p style="color:blue;">WATER</p>
            <br />
            <input type="submit" value="Register" id="play" />
            <br />
            <br />
            <a href="login.php" style="color: black">Log-in</a>
        </form>