Diablo 2 items is one of the most well-known examples of the action-RPG subgenre. Although players level up

Diablo 2 items is one of the most well-known examples of the action-RPG subgenre. Although players level up, choose character classes, and manage a variety of spells and equipment as in a typical RPG, all actions are done in real time, as in an action game. Diablo in many ways resembles roguelike games, the main differences being more realistic graphics and the fact the game is in real time, rather than turn-based. Diablo was influenced by Moria and Angband.[2]

The majority of commands in Diablo 2 items are executed by the mouse. Players click on an area of the screen to direct the character, and click on enemies to attack. However, learned spells can be assigned hot keys using the function keys on mouse-over, as well as several text exclamations (e.g. "Help me!") that could be edited in a configuration file.

Diablo 2 items is highly replayable thanks to its randomly generated levels, with every map that the player encounters being unique compared to the last. This randomness extends to the monster population as well, though they are generated from a group appropriate for that level. In addition, in single player mode there are only three core quests as the rest of them are drawn from several pools, making it impossible to complete every quest in one playthrough of the game. Either way, only the last two quests are compulsory (although it is necessary to complete the voluntary missions to gain experience and items, and to learn more of the backstory). Given this arrangement, no two playthroughs of the game are ever exactly alike.

There are sixteen levels of the dungeon, divided into four areas. Each area has a different appearance, architecture, light level, monster mix, and musical soundtrack. The first level of each of these areas (levels 1, 5, 9, and 13) each have an additional exit leading back up to the town of Tristram. In single player, these entrances are blocked until the character opens them from the dungeon side. For example, the entrance from level 13 to town is not visible at first. When the character reaches level 13 from level 12, and then finds the stairs to town, they may go up, and the entrance (a glowing crevice) opens and is available for two-way travel from then on. In multiplayer, the entrances to town all start in their "open" position, but with a level requirement to access them from town. A character that does not meet this level requirement will have to either gain more levels, or reach that area by completing the preceding area.

Levels 1–4 are set in the Cathedral, with a fairly straightforward layout, large rooms of regular size connected by wide corridors and frequent doors and grates. Levels 5–8 consist of the Catacombs, which are very dark, and have a convoluted and confusing room layout. Levels 9–12 are the Caves, which contain powerful and magic-immune monsters, and a very complex layout, with rivers of lava and fences blocking the character's path in many places. Levels 13–16 are set in Hell, infested with the mightiest monsters in the game; the layout is straightforward, but doors and grates do not exist, preventing the character from easily controlling his enemies' movement. The 16th level of the dungeon, lair of Diablo 2 items himself, cannot be accessed until the player has completed the quest to slay Archbishop Lazarus.