We all know how popular an energy system is in today's free to play games.
I think this would be a great feature for the GameSparks platform.
While I'm sure it wouldn't be too difficult to code using Cloud Code, a built in system that can be managed in the portal would be awesome, and a good selling point for GameSparks.
Thanks for the suggestion Greg, we will keep this in mind as a few people have asked for it.
Like you said, the cloud-code does allow you to do a lot, and these kinds of resource-gen systems are really down to how you want to design them.
Check out this forum post about the topic [https://support.gamesparks.net/support/discussions/topics/1000033548] and let us know if we can help you further.