A couple of thoughts:
1) Your quickstart ends with a command to remove the test container, but leaves other resources, like the pulled image, billed at 10 cents/started GB intact. That's probably going to surprise some people that start to play with your free credits, and then maybe end up eating that/getting a (small) bill at some point due to dangling images.
Might want to add a "hyper rmi nginx" on the end, along with commands to remove the shared volume?
2) The binary for Linux seems to work fine under "bash/Linux subsystem for windows" on windows 10.
3) Inbound bandwidth on the smallest images are abysmal - I didn't test bigger ones, so I'm not sure if are just those that are oversold/under-provisioned. I got 2-300 Kbps from Ubuntu mirrors and http://speed.hetzner.de/1GB.bin on a fresh Ubuntu container -- while from my small vps on Leasweb[1] I got a solid 10 MB/s (basically 1 Gbps).
Granted the small VPS is almost 5 Euros a month - but that includes an IP - and drops with a longer term commitment (again apples to oranges, I know -- the whole point of containers on demand is that they are, well, on demand).
And Leasweb is pretty close to Hetzner - but still, at least breaking a solid 1MB/s should be an absolute minimum.