This is a really interesting concept! It's cool trying to think of alternate words for actions like movement, so you can avoid burning through the same few letters every time.
I did find the interface a bit clunky, with having to rewrite words after every action and deleting the "???" text afterwards. I wonder if perhaps being able to control the second phase with the numpad (selecting the 9 different spaces with the 1-9 keys) might speed input up a little bit, rather than having to change phase with space? Though not everybody has a numpad.