This is one of the greediest games I have ever played. The game is great and the visuals are stunning but it takes so much energy to do anything and energy regenerates s...l...o...w...l...y. SO slowly!! Of course, the game offers you the opportunity to purchase energy .. At exorbitant amounts for not much energy and IF you do cave in and purchase energy - it is used up so rapidly it is just not worth it. Really ... just horrendously greedy game makers.