I would recommend Xcom: emeny unknown as it's a highly suggestive sicence fiction tactial roleplaying game, and I must say it's worth a lot of time investment planning managing base resources, Difficultys That sure will keep you to the edge of your seat +DLC within is mostly a must have and why not throw in the Long war modifcation to make it really challanging for those who can withstand the good hardcore challange.