Very nice demo, I like the up-and-down sliding effect.
On the pure aesthetic side there are 2 things to add/change IMO :
1) Work on the mirror effect (not very important but very nice!), someone already mentionned it before but I don't remember who, sorry...
2) Remove the transparency on the 2 stacks of covers on each side, I find opaque covers more beautiful.
3) (yes I know, I said 2) Add the ability to switch from this mode to a mosaic (like system menu). Good for people who have a lot of games ...
On the dev side, I agree with people who said it could be good to merge this GUI with the core loader or to separate front (gui) from back (core) and provide a clear api to communicate, but I understand it can be hard (or maybe impossible) to have a such organisation ...