Good evening QuasiKomodo and welcome to CH
Nice choice on the laptop looks great. The bad part is for heavy gaming and battery life is almost a oxymoron. When a PC is heavily used the battery takes a beating. My recommendation's would be buy.
#1...Buy as much memory as you can afford
#2...fastest CPU
#3...fastest GPU
#4...get the biggest battery possible
#5...also get a SSD hard drive (solid state drive)
The reason for the above is the easier a PC runs an app / game the better it will be on a battery if that makes since and also shut off lighted keyboards and only have the necessary programs running in the back ground.
Last I knew Alienware did have a battery optimizer that used to come with the laptops and there may be a 3rd party tools but none that I trust. There may some other folks on CH that may have one that they would say works.
Hope this helps,Mike