This game was just released a couple weeks ago, and it has been loads of fun so far. It kind of plays like a more complicated version of war.
You can get by playing it just a little bit at a time, but even if you want to play a long time the energy recharges fast enough to allow it. It's completely possible to go F2P for the single player campaign (which is very long and exciting btw).
If you guys wanna check it out though my referral link I'd greatly appreciate it
https://lcd-prod.appspot.com/rvKD2X7Da