macbook pro 13 late 2013 for gaming

No Mac notebook is meant for gaming. Buy a Windows box for that.

I agree with LowLuster that most games run on Windows. It will be less expensive to buy a PC or a graphics card for a PC you might already own.

If you want a Mac and also gaming then you can use Bootcamp to dual boot your Mac on OS X and Windows. Purchsing a MacBook Pro would be much less expensive than purchasing a MacBook Air and a PC. Similarly configured MacBook Airs and MacBook Pros cost about the same.

The Intel Iris Graphics processor works well for gaming. It is a medium-speed graphics processor, significantly faster than the Intel HD Graphics 5000 in the MacBook Air and not as fast as the graphics in the expensive 15” rMBP models.

If you purchase the $1,300 rMBP, add $100 for the 8 GB RAM upgrade. Games tend to like lots of memory. Then consider your storage needs. Is 128 GB enough? You will not be able to upgrade the SSD storage after you purchase it so purchase enough storage to begin with. With 8 GB of RAM, the 256 GB option will cost only $100 more.