Very nice interface
This game has the best interface I've seen yet for nonograms. I love how you can just click and drag to mark off multiple numbers and boxes, even when the boxes are diagonal to each other (useful for making squares). A lot interfaces force you to check of numbers one at a time, or only let you mark off columns or rows, but not boxes.
Still, there's a few improvements I'd like to see.
First, it'd be nice if dragging would just repeat what happens in the box you click on--like, if I click a box to drop an X, dragging to other squares would drop Xs in them, too, even if they already have Xs. Currently, it seems to toggle boxes--like, if you're dropping Xs, and drag over a box with an X in it, it'll clear that X.
Another thing that'd be nice is if once you solve a row or column, the game would automatically fill in the Xs for you.