Word Twister gives you a set of scrambled letters and a clock: make as many valid words as you can from them, with longer words scoring more.
The shuffle button is genuinely useful — seeing the same letters in a different arrangement is how the brain spots anagrams it was blind to a moment earlier.
Longer words are worth more, but taking every short word available while you hunt for a long one is what produces the best totals.
Yes, meaningfully. Seeing the same letters arranged differently is how the brain finds anagrams, and it costs nothing.
Yes — tap letters to build words. Nothing to install.