That was my first thought too - "here are some example instructions, moving the cursor around changes some registers... but I want to assemble a little program to try it out."

I think an "emulator" that doesn't let you run your own code in it is not an emulator. It's only an interesting visualisation.

As I pointed out this project is in it's infancy. I merely tweeted about progress and it ended up here ;)

See [status](https://github.com/thlorenz/visulator#status) -- indicating in experimental stage.

I'm planning to allow loading binaries and also editing assembly (assembling it in the browser so the CPU emulator can run the opcodes).