what kind of game, cpu heavy or gpu heavy?
The Guide for gaming laptops:
First Graphics
800M+ series from Nvidia should keep you going for sometime, I personally have the 850M and its perfect for what i do. (Minecraft at 250 fps)
Cpu:
Depending on the type of game you might wanna go with 2 -> 4 cores, most laptops have intel cpu, and look for one with hyperthreading.
And the clockspeed should be around 2,50 GHz and Boost 3,00~.
Ram
The clockspeed of the ram doesnt always matter, like in this case, I have 8 gb of ram and can upgrade to 16 gb if i wanna.
so choose one where you have plenty of ram, and upgrade if you need to.
Screen
Biggers is always better, and so is the resolution. 15,6 -> 17,3 Inches is pretty good, and go for 1080+ resolution. And find one with 60 Hz monitor instead of 30 Hz, (Hertz is a updating unit for screens and other devices. 1 Hertz, 1 update per second.
Harddrive:
If this is for gaming, i would recommend a large harddrive, with the possibility to upgrade to an SSD.
And the probably the largest problem for gaming laptops, is the noise...
some of them have bad ventilation and others sound like Jet engine, some laptops have dual fans setups which is very good for being quiet and cool.
Good Luck Mate! (M8)
I personally recommend MSI and Asus.
Have a nice day