Now in the game you need energy for just about everything you need it for elevators, weapons, and etc. so everything fun in the game costs energy and the rrecharge rate of energy is 24 hours in real time. im just saying why not instead of trading in the minerals you earn in the depths for coin how about you trade it in for energy and maby make elevators cost half as much and when making a weapon the energy price can be 10 and maby decrease recharge times to half as well just an idea