The combinations you can make to move the tiles are not limited to using the ones located right next to them, rather you'll also be able to exchange the tiles diagonally.
The longer the words the more points you'll get, although you'll have to bear in mind that some of the letters give you more points than others, so if you make good combinations you can add up many more points.
The more points you obtain, the sooner you'll go up a level and the more advantages and help you'll get. This way, when you pass on to different levels, Word U gives you a series of bombs that explode and give you additional points.
You can only create words in English.