Requiem uses the Havok physics engine for ragdoll physics in its animated death sequences for each enemy, with effects such as decapitation and limb removal in keeping with its horror-oriented theme. Certain monsters appear at night in certain areas during the "in-game" hours of 11:00pm to 2:00am, these `Nightmare Monsters` are far stronger than the local mobs and yield increased exp along with higher chances of "rare" item drops. These monsters are usually fought in mobs.

With several different item enhancement systems, players can create new items or upgrade and customize existing ones. These upgraded items are created through the use of compounding and reinforcing by using various `xeons`. There are numerous xeons throughout the game and the variety is nearly limitless. There are so many enhancements that can be applied to any item that it makes it worthwhile.

A player can transform his or her character into a ferocious creature known as a Possession Beast. By leveling Possession Beasts, players can equip it with an even deadlier selection of various skills, abilities and equipment. However, players are required to fill a `Hardcore Bar` up by killing monsters to a minimum of at least 90% before one can use his or her Possession Beast. The Possession Beasts are obtained by completing the "Forgotten Relics" quest at level 23, however cannot be equipped until the character attains level 25.

Requiem features battlefields meant for team-based player-versus-player combat. Only the victorious are rewarded with special items used for obtaining the rare weapons and armors. While the game`s scope allows team battles of up to 96 players per side, as of now only 8-vs-8 battles are functional. Player-Killing is a function of server; on some servers, it is restricted to the aforementioned battlefields, whereas others allow PK at any time. However, killing another player results in restrictions being imposed on the player`s character, such as not being able to buy from vendors for awhile. These effects wear off over time.

Certain areas in the game require a party of 4 or more. These dungeon areas are filled with strong enemies to increase the difficulty (and, theoretically, the excitement) of the raid. Typically each dungeon concludes with a "raid boss," enemies that are far superior to any one character; these bosses require groups of 15 or more to defeat. However, such dungeons give access to the most powerful items in the game. Finally, "town raids" may occur when a random raid boss enters a town (which is normally a non-combat zone) and players are given the option to engage it.