In the first demo you use WASD to move around. Personally I use a very different keyboard layout but that's not what I was going to say but actually while we're on the topic it should be noted that in some countries they use AZERTY [0] which means that more people are actually affected by the particular choice of WASD than just those of us who have chosen non-standard layouts like Dvorak or Colemak so maybe consider making it possible for the user to define keys to use after all even though I wasn't going to suggest that.
Anyway, the thing I was going to suggest was to allow click-and-drag with mouse to be used in order to look around. Also touch-and-drag on mobile devices. And provide on-screen buttons for mobile device users to move forwards and backwards and sideways.