It would have been 2 on features, but the parser option (unlike filling in 3 fields) was done well. However, none of the die buttons worked on my Mac.
Now, to get picky:
The interface is too big. Single results should be in a text box. The paper tape should probably be like the one in calculator.app, separate, resizable, and with a clear button.
Otherwise, it is what it should be: simple, clean, and efficient.
Playability and Graphics/Sound are not applicable fields. If there's a mod out there reading this, you need to have a NA response to your category ratings!