Ok. There is a lot I want to say here, but I'll keep it short. This isn't really a game, but I understand it's an interactive tool, and not really many other places to put it. So, FYI, my score DOES NOT knock you down points just because this isn't a game.

There is a LOT of functionality here, this seems like a really cool tool, and I could spend hours here messing around. But it's overwhelming, and after about 20 minutes, I still can't quite figure out how to get this thing going, and I use photoshop, apophysis, coreldraw, and illustrator on a near daily basis, as well as 3d modelling programs. I can tell by watching the premade shows, there are some amazing things that can come out of here. But again, it's just overwhelming. We really need a little bit more direction than this. Why not integrate a tutorial. Just a simple one with a couple shapes you draw on screen, we copy, and execute, teach us the gist of how things work, and get to to a basic point to be able to draw shapes, do simple color and transforms to them, work with 2 or 3 layers, adjust timing, start a show, and export it. I think the various effects become self-explanatory if you can show us how to get to that point.

I can see most people just getting lost in what to do here and not having the patience to really dig into this. Like, I really really really suggest integrating accompanying tutorial videos.

Suggestions from what I can figure out. I'd like to be able to export as an SCR or GIF. I don't know if this is possible, but it seems like these beautiful dynamic scenes you're showing us, and we're making, should export into a format that better lets us maintain the flowing forms.

For some reason, It feels like this is on the border of becoming a bullet-hell dodge game. I'll refer you to Bullet Heaven by Matt-Likes-Swords as to why I think this.
https://www.newgrounds.com/portal/view/566417
Yes, your kaleidoscope is drastically different, but I'm brainstorming applications for this type of program.

Wow this is so fun! I'm yet to figure out the rest of the options, but I think this is a really creative game idea, and very fun to paint in. Only suggestion I would have is some kind of instructions, either in game or in description, especially for key features such as saving the game. Keep up the amazing work :)