1) I wouldn't call the numbers you enter into the boxes "scores." They are really weights - I don't know about others but I got confused by that at first.
2) Is there a way to substring searches? E.g. If I type in "debate" I might want "mydebate" to come up...
1) You're right, but the boxes (and columns of numbers) are probably going to disappear in the next version. Maybe we'll have sliders or radio buttons to adjust between "Important" and "Don't care" for some properties.
2) Real substring searches are not supported because they are expensive. But your example is supported: type "debate" in the second keyword input field for suffix matches.