does it cost money? coz it says that I have to pay 5 euros to verificating my account

no, there's a download link above that. I will try to make that clearer.

"Unable to install or run this application. This application requires your system to be updated to Microsoft Common Language Runtime Version 4.0.30319.0."

what should I do?

I think that is a bug with Microsoft and the fix was to reboot. Don't know if it works though. Thanks for telling me!

will do brb~
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doesn't work :/

That sucks.

There's no quick fix for it since it's on micosofts side.

will be rather great to be able to create own "server / room" and invite people there to draw together. this will be great feature and will be rather usefull for artists. + options to export painting in various formats

Yup, I have plans for that, but would like more people to paint in the default painting first. The exporting option is a good suggestion.
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Right now, when you publish, a 300 dpi copy is saved on your computer, so you could stitch together those. But you can't export a combination of artworks as of now.

i draw shit with mouse! but still....
@hampa