From the main page: "It's important to note that the above are only the layers of the factory keymap. You can redefine them in any way and create multiple, custom, application-specific keymaps."
I also would avoid this (otherwise nice) keyboard if Fn could not be changed to a standard modifier.
You can make Backspace emit Ctrl, Enter emit Alt+Tab, or make the Right Shift play back a macro.
I'll keep an eye on its development and availability. Thanks.
PS: I'm not your target audience (I use my laptop keyboard almost exclusively) but great job so far!