It might help if you did some smaller programs first where it is clear what the numbers in the grid really mean. Do those numbers map over (assemble) to the instructions?
I guess they do but I never could find a table that said "store" is this number...
It does look cool though!
In addition, once you have filled in the boxes a little, you can step through the code and the blue box under the grid will give you another, very brief bit on the instruction that your program counter is on.
Thanks for asking!
If I use the buttons to run the existing program it does nothing but check if register A is zero, jumps to cell 254 and executes the error instruction.
There is something I'm missing but perhaps what I am missing is not so obvious.
Are you sure you can't edit once you highlight a cell? If so that's probably a bug.
Sometimes it will allow me to update the cells but whatever I type merely appends to the existing contents with no obvious way to clear an individual cell.
Now it seems to work... sort of... sometimes it'll clear one of the characters in the cell and sometimes instead the global handler traps it and attempts to navigate to the previous page in my web history.