It's time to test your vocabulary with Ninja Crossword Challenge, an educational puzzle online game for everyone, and a free game for kids to improve their vocabulary. All you have to do is fill in the words in the grid, the game has more vocabulary than you can imagine, ready to take on my challenge? crossword game, vocabulary game, online crossword, kids vocabulary, word puzzle, free online game, brain training, cognitive skills, vocabulary builder, educational game, ninja crossword, challenge, word skills, memory improvement, concentration, learning game