You can dispatch the hungry ‘O’s with a few clicks of the mouse, but like the fast-moving ‘Zerg’ enemies in the popular PC game series StarCraft, you’ll soon find your page overwhelmed and the ‘O’s do their own version of a friendly victory dance by lining up to form two ‘G’s, which I presume is short for "good game." There’s an option to share your score on Google+, or clear the screen and try again.
I'm not sure there's a practical method, or reason, for gamifying the search engine -- it's usually a very transactional experience. But, if there’s any way to make using a search engine more fun, I have yet to think of a better example than this, along with the often delightful Google Doodles. Bravo, Google. Bravo.