Well I can't even imagine how much fun that would be to create images and movies like that.

What if it can also capture your imagination? Designers, architects etc. could just project their imagination to the screen. That's a really cool idea, I think I haven't seen that even in sci-fi movies. What about composers, could they generate music just with their brain? I recall that it has been shown that imagining and actually sensing provides same kind of response from brain waves. The only downside to this right now is the size and expense of fMRI machines, I hope there would be a more available method.

Also, it would be very very nice if they open-sourced their data so people could develop better reconstruction algorithms.

This is really really exciting. We are in the future. What I find odd is that they have reconstruct the video by combining different video clips, like there wouldn't be any systematic transfer function from brain activity to images and vice versa, but just matching sets of data. Or maybe deriving the transfer function is just really complicated and this seems like a first step to prove that it could work.