giantbomb_api.php

<?php

const API_KEY = 'xxx';

$url = 'http://www.giantbomb.com/api/game/3030-4725/?api_key=' . API_KEY . '&field_list=name&format=json';

// using file_get_contents
$context = stream_context_create(['http' => ['user_agent' => 'API Test UA']]);
$response = file_get_contents($url, false, $context);

echo $response;

// using curl
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_USERAGENT, 'API Test UA');
$response = curl_exec($curl);
curl_close($curl);

echo $response;