About twelve hours ago, I downloaded and installed the latest AMD64 snapshot (#1063 in /etc/motd). When booting it hits an infinite loop, repeatedly printing "Process (pid 1) got signal 4" to the console.
When I boot to a snapshot ramdisk or bsd.rd now, it hangs at "root on rd0a swap on rd0b dump on rd0b". This happens on two different USBs, and whether or not my primary drive is even connected to the machine. A half hour ago, I downloaded a newer snapshot ramdisk from ftp.openbsd.org. When booted to, this one immediately hits an infinite loop, printing "Using drive 0, partition 3." to the console. I'm pretty confident that this is an issue with the snapshots and not my machine because the 5.7 release images boot fine. I suspect that the devs are already aware of this, but I thought I'd mention it.