Scratch is an educational site made for schools. It is not meant to be an actual game engine. In fact, I think that it is quite literially stated somewhere that Scratch projects will never be able to be used for money or be able to be copyrighted. If you want the chance for your game to be copyrighted, you'll have to make it outside of Scratch, and I think you have to be a certain age to legally be able to copyright your content, maybe around 16-18 in the US but I'm not sure.
edit: king of the page

I will point out that everything on Scratch is licensed under CC-BY-SA 2.0- everything on Scratch has some rights reserved to the creator.

Any case where someone (on or off of Scratch) does not give credit to the creator is illegal.

Any case where someone modifies something on Scratch and gives credit to the creator, but does not also license it under CC-BY-SA 2.0 is also illegal.

In both cases you have the right to sue the person violating the license (although if it happens on Scratch the ST would much prefer that you just report them).

Za-Chary wrote:

(#20)

DifferentDance8 wrote:

crazyfrogcat wrote:

but fan games are copyright required

Yes, in most cases fan games are copyrighted. However, in some cases they might be considered “affectionate parodies” which are parodies which fall under Fair Use.
(good luck trying to explain that to Nintendo though)

Probably off-topic, but Nintendo has seemingly been okay with Scratch projects. I don't recall any Mario projects getting DMCA'd before. Either Nintendo is not aware of Scratch, or they understand Scratch's educational mission.

i think Nintendo doesn't even know scratch thank you

I get a sense that the discussion going on is rather circuitous at the moment, which isn't helpful, so it's probably best to end the discussion with a more clear-cut answer.

One of the underlying values behind the design of the Scratch website is the ability to learn by studying other people's works and building upon them - hence the slogan "Imagine, Program, Share". To allow that to happen, projects in question can't be fully copyrighted because it would restrict the ability for someone to learn in this capacity. This is why all projects are covered under a CC license and cannot use a traditional copyright mark.