GraviTrax The Game - ImpactGraviTrax The Game Impact This hammer themed game set features 30 challenges with varying levels of difficulty, all including the use of the Gravity Hammer that can be utilized by one or more people. The game cards show an example of what pieces to start with and what pieces can be used to complete each challenge. Solutions to each challenge are found in the included solution booklet. Each set includes 30 challenge cards and a variety of base, rail,