Upload & Sell: On
Double exposures have long been a part of photography WAY BEFORE software ever was even thought about ... nicely done. I figure, if it can be done in camera or in the darkroom with film & paper, then the fact that its being done in the digital darkroom is no different.
A lot more photographic technique to pulling it off well than a few special effects mouse clicks ... good job, I'm diggin' it.
Part of photography absolutely. Part of photo contests is another matter. I certainly don't want to beat a dead horse though. I do like the pic, you can never have too many chess pieces.