First of all, welcome to Newage! Glad to see more stage creators, I hope you enjoy your stay.
- How come you've got semi-coloned parts in the .def for sprites that don't exist? You could just remove those, unless they're there with reason.
- You could decrease the huge size of some of the sprites if you cropped them.
- Not an issue, just a suggestion (for messy mugen players) perhaps you could change your .bgm to be the name of the .sff and .def? lol.
That's all I could really see. All in all a very interesting, simple stage with a nice touch on deltas. Extremely unheard of for stages like this to turn out as good as it did, checking out the guys deviantart page I see some great work, any plans on doing the SOR remake?