Create 2 has all of the same navigation features and sensors as our Roomba 600 series vacuum cleaning robots. That is to say, it does not have systematic navigation or obstacle avoidance. You may confine it using virtual walls. If your project requires automatic room coverage, such as a roving security bot, you can make use of the built-in coverage algorithm by starting a cleaning cycle through the Open Interface.
Create will return to the dock when its battery is low only if you have it running a cleaning cycle. If you are directly commanding the wheels yourself, it will not automatically return to the dock. You will need to monitor the battery state yourself, at which point you can command it to return to the dock.
Sensors available include wheel encoders, downward-facing IR cliff sensors, forward-facing IR light-touch and wall-follow sensors, the IR receiver for dock/virtual wall codes, the dirt-detect sensor, buttons, and the bumper. A number of internal variables such as battery state and motor current are also available. For actuators you have the two wheels, three cleaning motors, and LEDs.
Here is a link to the Create programming manual: