Epic.
Make your own rules and let particles behave and interact however you want.
I recommend downloading the game for better performance: https://drive.google.com/drive/folders/1SJ28CmqQdlW6arOpUGYR6jboLpTh1uZ7?usp=sharing
You can delete pixels with the right mouse button.
If you need help understanding the editor, press the '?' to open the guide.
Epic.
Sandbox Sandbox? Love it.
Although pretty basic, creating your own particles is really cool. I think it would be better if there was more preset particle options or more behaviors, but I think this has some potential if it gets updates.