Yep, that is definitely interesting, and I don't mean that as a euphemism for anything!

How hard is it to change gears? I know some hills where it would make sense to manually change gears before attempting a climb... but I also know rolling hills where it wouldn't.

Could you, by changing the tooth count of one sprocket or chain ring, get the chain length the same for both gears? I suspect you could do that; then you could have a front derailleur and a very primitive rear derailleur (like, another front one, but upside down) and shift on-the-go. Such luxury!

I guess, really, we need to hear what you think of this in a year or so. It's the kind of thing that is great fun for a while but it may get old. If you're like me, you'll continue to diddle with it as long as it's not perfect.