Doomguy

The 22nd Century

The period between 2100 and 2199.

The Locked Door

It's the designer's go-to guy. If they want to steer a player in a given direction they'll lock an in game door and force the player to find a way to either unlock it or find an alternate route.

Tyrant

Ultimate Weapon

A powerful weapon often found near the end of the game that is significantly more powerful than other weapons. It can also be the last weapon in an RPG game that does drastically increased damage compared to previous weapons.

Union Aerospace Corporation

UAC are a fictional research company located on Mars.