There is a theory that for a puzzle game to interesting it has to be NP-hard. Something about how otherwise your brain is too good a latching onto the "trick" and the game is boring.
the rubiks cube is in P space, but has a large state space
towers of hanoi is also in P-space, has a trick to latch onto, and is still popular - though maybe this strays from being interesting and is popular for different reasons
the rubiks cube is in P space, but has a large state space
towers of hanoi is also in P-space, has a trick to latch onto, and is still popular - though maybe this strays from being interesting and is popular for different reasons