All users will need to download a complete install of the IDE due to a bug in the patches. With Android Studio 2.2, you may have noticed the larger download sizes than previous versions of Android Studio; this is because we now bundle a build of OpenJDK with the IDE to address various font rendering and stability issues. Note We recommend you keep 2.1.1 and 2.2 Preview 1 installed side by side; they already use separate settings and cache directories. More information on how to install multiple versions simultaneously.
Updated June 23rd: Due to a bug in the patches we can only offer full downloads. If you patched and can't get studio to launch, please download a full update. You can follow the progress of this issues here.