Hi AlexData-Hawkhill,
This app should work on most modern CPUs. Very old CPUs would still work but they will take too long to generate an image though.
In terms of RAM, it really depends on the size of the image you're generating, but I would say 16GB is a reasonable minimum.
No need to have extra space on your HDD, other than just the needed to download the app. There's nothing extra that the app creates other than images, which are very small in size.
I have planned to add GPU support for this app, as well as a macOS version. Still busy with other apps, so it will take some time.