It is always nice to see projects like this. Creating a simple interpreter isn't a hard job, but it's still pretty educational.

One thing that you'll benefit from is documenting the instruction-set, and usage a little more clearly. For example my own toy language was written in C here:

https://github.com/skx/simple.vm

And I think I did a good job of showing how to use the instructions. Then for fun I rewrote it in golang https://github.com/skx/go.vm which showed some interesting differences.

Your own tastes might differ, but I'd think after the interpreter a compiler/decompiler would be good next steps. Makes it a lot easier to write code/programs in your assembly!