Yes, you can playback from the camera. Hit the mode button either twice or 3 times, but first make sure you are not recording. The first mode is auto-record video, the second is 4:3 recording and the 3rd is photos. After that, the mode is playback. Make sure you go into playback mode after you have recorded something. Then hit the 'REC' button when in playback mode, I believe that will 'Play' the video. This is all off the top of my head, so I'm going from memory, my advice may be a little off, so dont go by it exactly, but generally it should work.
Also, I would boot up the device, make your settings, then hold down the power button for 3 seconds to do a proper shut down sequence. After that, the settings should hold. I was having issues where the device would turn on when I switched the car on, but then it would cut off when I turned the car off. To fix this, do a proper boot off sequence when the car is running, then shut the car off, then turn it back on. Then it should hold your settings, also you should see a shutdown splash screen when the car is shut off and you power down the device. This should happen everytime. If it doesnt, something is wrong.
You are running the same firmware I am, and I had similar problems. Once I did a proper boot up and boot down procedure, everything was fine. Also, format the card in the dashcam, not in your pc/mac. Insert it, then format it. That worked for me.