I gave it a try, and I was impressed. The performance was very good for a GDK app. In most cases, I get about 30 FPS on this laptop, however your program ran easily at 60. As for the actual gameplay, I found it pretty interesting, a good sort of puzzle. It had an almost "Rubik's Cube" feel to it, in that there are certain ways to reposition the block, certain algorithms, that once known make the game less about guess work. Well done!
EDIT: I guess everyone is posting specs for reference...
1.6 GHz Intel Core 2 Duo
2 GB RAM
Intel 945GM, 128 MB (Notoriously terrible chipset)
Windows XP Media Center Edition
My site, for various stuff that I make.