Love, love, love this game. Hints only work up to about level 49 or so (can't remember exactly what level), after that hints are disabled. I have been stuck on level 76 for a while.
Great puzzle game with plenty of single player modes (regular puzzle, timed, infinite, etc.) and great single-cart multiplayer -- both competitive and co-op.
Nice, low intensity puzzler with great graphics and music -- well worth the price.