goriley

Im having troubles with my cities skyline on my mac. I had bought it off Steam and when i launch the game everything is fine until about 10 mins into playing. The game starts to lag and glitch and then all of a sudden it freezes and the colour wheel pops up and i have to force quit the program. While I'm trying to force quit it says "Application not responding". I have some photos attached to show what happens. Let me know if anyone has a resolution! Also, these are my specs