Great game, 5/5. Maybe a little bit too easy with the way exp. points are given out, but otherwise great gameplay. Only things I'd suggest is a basic auto attack, and a more noticeable graphical alert when being attacked while on a menu, (for those of us who mute the sounds.)
Great game, but making people wait nearly two hours to play for five minutes is ridiculous. I can understand wanting to make money for something so much time was put into, (at least on flashy graphics,) but if ad revenue isn't enough, then selling special content should be. At least most other games that use an energy system let you upgrade your maximum amount.