There are only 4 rules of Dexev:
You can move blocks to the left or right, as long as there's space.
A block on top of blank space will fall into it.
A block touching another block of the same type will vanish.
A level is finished when all the blocks have been vanished.
More than 1000 levels available in full-version, from easy for childs to impossible for Einstein.
nice graphics, easy rules, playing with fingers, scrollpad or arrows.
Unlimited undo, best scores per level.