From the front page, "All assets must be created during the jam.". One would assume this applies to logos as they are also assets.

There are a number of really excellent GameBoy box art templates around like this one:

https://www.deviantart.com/blueamnesiac/art/Game-Boy-Box-Art-Template-337084194

Would using something like that in addition to our own cover art be acceptable or would it be better to roll our own faux box art frames?