Just a thought…
-spelling words backwards would be trippy and much more difficult to conceptualize
-changing the colors and giving negative instead of positive feedback (wrong letters show only)
-parts of speech (adjective, verb, noun)
-themes (animals, colors, names, food)
-varying word lengths for the above suggestions
-timed puzzles
-build your way up/down (letters automatically carry over)
-letters given, change them to find the word
Again, these are all just suggestions. I simply bring them forward in hopes that the innovation of commfolk may continue on and the monotonous and continual destruction of big corporations will end.