Blocks with letters on is quite simple at the beginning, move a few blocks along a grid to form a word. You're rewarded with a short animation of the word in action.
The first order of business is to unscramble the letters and figure out the word. Each puzzle has only one solution, and you don't necessarily use all the letters each time. Once you've got the word figured out, it's time to plan your moves to get the letters to their final positions in the yellow squares. New elements are added as you progress, like sticky squares, switches and pivot points.