Thanks for the entries, folks. FWIW, 14 people entered 29 levels. I've played about half of 'em, and I'll be sifting through the rest this afternoon and tonight, putting the favorites into the game. I was planning on having about 12 levels in the game, figuring that would be plenty for a quickie web-game. I'll hang on to the rest in case I decide to make a standalone commercial version of it.
I'll email the winners tonight or tomorrow, and I'll post 'em here.
Also, thanks to "Fruny" in the gamedev.net chatroom. He sent me a half-dozen very good levels, but refused to be involved in the contest because he didn't like PayPal for some reason. Figure I owe him something, even if it's just a printed "thank you" :)