Ok, I'll try to save your life...
You can add two entries,
IN THIS ORDER:
Item 1:
From URL:
/index.php[[.question-mark.]]option=com_content&task=view&id=120
To URL: http://{siteurl}/test2.html
Item 2:
From URL:
/index.php[[.question-mark.]]option=com_content&task=view&id=12(&Itemid=43)*
To URL: http://{siteurl}/test.html
This because if more than one item matches with current URL, ReDJ takes the first one.
So when you call url with id=120, both match but item 1 is applied. And when you call the others, only item 2 matches.
In general, when you are not able to create a single regexp that matches all your needs, you can solve creating multiple items
putting longest entries first.
Let me know if you are save now,
Luigi