Incredibly polished game with mechanic that fits the theme well! I have no idea how you could pack so much into the 48 hours, but it puts you into the top games for the jam in my book.
One small critique would be to allow the letter you want to work with to be selected with a left click. I found that I would drag a letter into place, but then if my cursor ended up over a different letter I'd be modifying another letter unintentionally.
+1 for the working scoreboard and level maker!