Page loading is very fast thanks to caching page thumbnails in profile directory. Actually, on my machine (64bit Debian on ThinkPad R61 with Core2Duo T8100 2,1 Ghz) page loads in 200ms and on very slow Toshiba netbook (32bit Windows 7 on old single core Atom) it loads in 2s.
Loading time on netbook is not ideal, though, but everything is very sluggish on Windows there, so that might have some influence on it too.
Changing of page background and keyboard shortcuts (Ctrl + 1, 2, ...) are not implemented yet.
While page background won't be problem, keyboard shortcuts will be quite tough. The main problem is laptop keyboards with lack of numerical block. In this case, clicking Ctrl + 1 emits Ctrl + + signal (and this keyboard is already registered to Zoom In). But I hope I'll manage to do it somehow.
You probably want to see some demonstration of how it works, so here you go: