Could your actual game be the "example game"? If not, then if I were you I'd just spend the time on getting my actual game done rather than make assets that don't directly get my game closer to being played. However, I'm not you -- although, you're among kindred spirits who identify with the desire to start new projects instead of finishing existing ones...
i will be releasing the assets under a non attribution creative commons. Not sure why i would want to retain the copy-write if I'm selling them to a public space like this...
FYI: With CC you retain copyright, but expressly state the license for use. In some countries (notably, USA) it's impossible to put your work directly into the public domain. Only saying, "this is now public domain", doesn't mean much. Under the Berne Convention
you're immediately granted copyright for your works. Using "Public Domain" works that haven't entered public domain through natural copyright expiration or by being created by government projects (some tax funded works immediately enter public domain) can be risky to adopters of the resources: At any later time (your lifetime + 70 years) you or your estate could choose to assert copyright over the works in use. This has occurred a few times, and is why CC-Zero
My retention statement was with regard to the practice of transferring of exclusive copyright to another game developer (who payed for your work), for which you can typically get more initial pay rather than if the assets remain yours, and you're free to re-license them to others (not just the dev you made them for).
You may also want to retain more control than only a non attribution license if you're selling assets to a public space in order to dictate distribution rights. Otherwise I can simply buy them for $5.00 and re-sell them for $1.00 to undercut your price and make money for nothing. Consider a CC Non Commercial license to prevent (or at least make illegal) such practices, and instead grant a limited commercial use license for purchase. To truly sell them directly to the public consider a crowd funding campaign (kickstarter?) whereby you get paid a set price once for the creation of the goods and afterwards don't have to employ artificial scarcity by trying to sell copies of bits that are in infinite supply.