All the best puzzle games stem from a very simple concept, and things don't come much simpler than Sokoban. Move boxes into designated positions in a room in the fewest number of steps, progress to the next, slightly trickier room. Irretrievably moving a box into the wrong place means resetting the level and trying again (you can't pull blocks backwards). That's it. No enemies (except a countdown clock in the arcade version), and no lives. Just a whole load of levels with very specific perfect solutions to find.
Of course, like all the best puzzle games it's incredibly addictive. Just beating a room isn't good enough - once that's done you get obsessed with cutting out unnecessary steps to find the most efficient solution.
Sokoban has been released in some form or other on just about every platform you could care to mention, some variants have added hazards and enemies which mixes things up a bit, but the original and best block-slider is still pure Sokoban.