I really loved this, DDR on flash is a pretty neat idea, and it'd probably be really good if there was a little more to this one. I loved the images, the song was alright (not the best in my opinion), and the accuracy of when you hit the keys was pretty on point. Really wish there was a bit more game than just this though.
Only had one problem, some of the flashing effects would go over the arrows and make it harder to judge when to press it. You could solve this by laying the arrows above and making it a unique color.