Official Quakewiki Video - Quake - E1M3 - the Necropolis

As hinted by the name of the level, this level introduces Zombies and proceeds to bombard the player with their existence. This means the player must quickly learn how to use a Grenade Launcher, the only weapon they have at this time that can hurt them. Furthermore, players on Hard/Nightmare will encounter their first few Shamblers. These beasts are rather difficult, meaning I start out struggling on my first encounter with them before eventually redeeming myself by the second half of the level.