I never realised until playing your game what movable type meant - single character blocks!
This is really polished and could be used in a classroom to show how movable type worked.
It was a bit small for me in browser mode - would have like a full screen option as the target boxes would have been easier to slot into.
Great subject matter to pick - one of the greatest inventions of all time.
As others have mentioned it does get repetitive without a timer or similar to make it competitive (multiplayer maybe?). I imagine it might be more fun to play in full screen on a tablet where you could use your finger to drag the letters.