Mac seems hotter than usual when FM 23 is opened

What temperature is it running at? May be worth getting a program to monitor it like Speedfan or something similar.

FM is designed to utilise all system power to run as quickly and with as high performance as possible, and a lot of Macs are will run hot given they way they're designed. 

We'd recommend making sure all fans and vents are clean and clear as this can help. 

Let us know how you get on. Thanks. 

Having done some research on this, Macs are designed to run up to around 100c before they start throttling performance. Macbook Airs especially as not really designed for gaming, but you can always make sure it's on a hard flat surface so air can easily get in and out. Beyond that you'd probably need to look at either lowering the game's graphics quality, or look at getting a cooling pad to help with temps.