Changes to the search engine include a left-hand navigation, highlighting search tools and refinements to better narrow down your search. It also allows you to quickly search news, blogs, images, and more. Plus, it's customizable, so depending on your search preferences, you can change the appearance of the left-hand nav.
Additionally, Google updated its font and logo slightly, keeping the page "minimalist and whimsical" but giving the page a slightly more modern look. Check out the official Google blog post for more information on the changes. Do you like them?