Halo is one of the more iconic video game franchises, especially over the past two decades. Of the games in the series, Halo 2 is often considered the best or most beloved Halo title, and to this day it is still played by many. In fact, as the community continues to dive into the many secrets of the series, there are those who are still uncovering surprises in Halo 2.

Whether it be the countless hours of online and local multiplayer or the distinctive campaign, Halo 2 is remembered as a quintessential first-person shooter. Recently a fan on Reddit shared an interesting find while playing through the campaign yet again, and the post has blown up.

RELATED: 343 Industries Addresses Whether 4 Player Co-Op is Possible for Halo 1 and 2

The post was uploaded by u/PBJsForever on Reddit. They show a clip of Halo 2 (which is playable inside of Halo: The Master Chief Collection) and the trading weapon mechanic with a Marine, which allows players to swap weapons with an AI teammate. What many players noticed and enjoyed was the witty comments of the AI Marine characters. What they may not have noticed, and what this Reddit user points out in the video, is that the Marine's facial expression changes based on the gun trade. If the trade is optimal for the Marine, it will smile and look pleased. If the trade is not favorable, the Marine will look unhappy.

This amount of detail in a game from 2004 is very impressive. The Halo community is one that often loves to share, whether that be in-game easter-eggs, theories about the narrative of the games, thoughts on future Halo titles, fan-art, and more. As soon as the post was shared on r/Halo, many fans chimed in with similar stories. What so many remember about Halo 2 was the amount of detail and character that went into the Marines and AI. For example, one person commented on how funny it was when Sgt Johnson, one of the main UNSC characters in Halo, commented "I thought we were friends" when the Master Chief takes the all-powerful Sniper Rifle and hands him the SMG.

Another commenter in the Reddit posts points out a story about a Marine who shares an entire story with the Master Chief. Apparently, he asks the Chief if he would like to see a holo of his would-be two-year-old child, who has been killed. Then, as the battle breaks out, he lets out his anger by killing his enemies and yelling out lines such as "that's for killing women and children" and "I can't take much more of this." He tells the Chief that his tour should have ended six months ago and questions why he is still fighting. It's this attention to detail--the kind that perhaps a large percentage of the player base will not even see on an average playthrough--that makes Halo 2 one of the best shooters in the eyes of many.

Halo 2 is available to play on PC, Xbox, Xbox One, and Xbox Series X.

MORE: Halo 2 and Lilo and Stitch Share Some Eerily Similar Plot Points