I think there will be some questions about the new contest, so I´ll start with my one:
Am I allowed to use different shader effects in one demo, or do I have to create a demo for each of them?

should this be a demo only showing the shaders, or also a demo with some things to do(playing)

You can use one or several shaders in a single demo.
You can add anything that you want to the demo; it can be playable, but this is not mandatory.

Is it allowed to hide the Lite-C- and Shadercode completely or must it be an open source demo?

Don't hide the code; this will prevent some people from stealing other people's work and claim that it is their work. You can use other people's shaders if you give them the deserved credit.

So, this is a "we exclude all extra edition users" contest?

so it seems, since its for shaders.. whoa... thats bad

I wouldn't want to exclude any users. I wonder if the trial version supports shaders; if it does, you could use it for the contest.

well it does support shaders but, lol, am pretty sure that anyone that has already bought a copy of a7 such as a7 extra or most lite-c users probably ran over the trial period.. oh well, i couldnt enter this anyways... i just wanna win the panel competition... later i'll aim at something bigger

@TheThinker:
If you have the ability to write shaders, it would really make sense to buy a Com.
It´s more like "we exclude all, who can not write shaders", or in general
"we exclude all, who have not the demanded ability"...but that is the character of a contest