This is a 10-y/o game made by Bungie. It is the original game in the Halo Franchise and still is awesome and lots of people play on the net and there are a lot of servers. The PC version has Banshees, rocket warthogs, flamethrowers, and a few extra bonuses over the console version. It requires no installation. It is a .zip. My close friend who I have known since the 2nd grade uploaded this.
Disclaimer:I am in no was responsible for the content of this post or websites referred to in it!