Hi,
this is not necessarily a bug but I found it would be placed better in this forum than in the actually game mechanics suggestions.

PLEASE, please, make the game not use it's full CPU usage while in background. I have a dated CPU and this game eats up almost 100% of all of my 4 cores. But why? It's minimized in full-screen mode! I cannot even see anything that's going on! Just put the FPS to 15 or 30 fps while the window is not in focus.

Thanks!