This is a very minor point, but it's difficult for me to move around in a first person environment without an inverted mouse.
But it IS just a tech demo. Changeable settings I would expect by mid-beta at least, but this is probably late alpha.
I started as a WSAD user in 1999, but I turned EDSF in 2004. (And I'll argue the letters should be arranged in "up-down-left-right" pattern, not "up-left-down-right" :p )
I'm more about the speed of things. I played a ton of twitchy 1v1 UT2k4 and had all weapons that would see real use mapped to a key right around my left hand. Also, jump on right click. Jumping was crucial to movement and the throw time for the spacebar had an (to me) noticeable effect.