Eye of the North does not feature new professions, but has 18 new "multilevel" dungeons, 150 new skills (50 of them restricted to PvE), 40 new armor sets, and 10 new heroes, in addition to the new items, weapons, and titles added as usual in every Guild Wars campaign. It is in part intended to act as a bridge from Guild Wars to Guild Wars 2 and will introduce the new races of the Norn (dwellers on the icy slopes of the Shiverpeak Mountains to the north), Asura (inhabitants of the southern part of the Maguuma Jungle), and Sylvari, all of which will be playable in the sequel.
Eye of the North continues the Prophecies story, which is told in three acts. In Act I, a great earthquake tears across the three continents of Tyria, Cantha and Elona, revealing entrances to a network of underground tunnels. From there, players enter into the homelands of the Charr (from the Prophecies story) to the north, the Asuras to the west, and the Norn at the far end of the Shiverpeaks. The story culminates with a battle against the Great Destroyer, the chief antagonist of the dwarven pantheon.
The majority of the Eye of the North story takes place in the "dungeons" that delve deep underground. Each dungeon has one to five levels, and completing some levels requires the players to acquire keys, use switches or levers, defeat bosses or interact with NPCs. The final level of the dungeon has a boss that must be defeated to clear the dungeon. Defeating the dungeon boss will cause a chest to appear, yielding loot for each party member.
Dungeons interact differently with the game's various maps than traditional explorable areas. The Mission Map normally displays an overhead map of the entire region, with unexplored regions blurred out but still visible. In dungeons, the entire mission map is black until the player explores a region. In addition, the mission map resets to unexplored when the player leaves the explorable zone. Similarly, the world map does not change to reflect which portions of the dungeon have been explored, and does not reflect the precise position of the player. Rather, the player is shown roughly in the center of the region on the map where the dungeon is situated. Also notable is that dungeon zones do not count towards the Cartographer titles that measure the percentage of the map a player has explored.
Earlier Guild Wars campaigns featured a small number of dungeons, such as Sorrow's Furnace in Guild Wars Prophecies or The Deep and Urgoz's Warren in Guild Wars Factions. They play a much more important part in the game play of Eye of the North, with a few gameplay alterations being made to accommodate dungeon exploration. Most Eye of the North dungeon levels have an area map located somewhere near the entrance. This map does not expose the layout of the level, but does place indicators on the mission map where key items (keys, bosses, collectors, etc.) are located. In addition, reaching certain areas of the dungeon, particularly the final boss, will place a marker on the overhead map, indicating where that location is.
Dungeon levels also frequently include locked doors which require a specific key to unlock. Unlike most key-like items in earlier Guild Wars dungeons (such as gears in Sorrow's Furnace), these keys are not carried by the player. They simply appear on-screen once the player acquires it, meaning the player is not hampered by the loss of their weapon and off-hand item benefits.
Eye of the North focuses more heavily on PvE accomplishments, such as titles. One of the new features is an item which acts as similar to a quest log, recording specific feats the player accomplishes in game play. Upon defeating the final boss of the dungeon, a new "page" in the quest log is filled in. Completed log books can later be turned in to one of the allied factions in the game for a large experience and reputation bonus.
Eye of the North introduced a number of "minigames" to the Guild Wars world. Each major faction has their own minigame which can be used to earn reputation points for that faction. The full list of these games is as follows: Dwarven Boxing : The player character wears a pair of brass knuckles and enters a round of one-on-one combat with a computer-controlled opponent. The player's normal skill-bar is replaced with a collection of boxing skills, some with unique skill animations. When a character's health goes to zero, he or she is knocked down; the player must then repeatedly use a "Stand Up" skill to regain energy and re-enter the battle. If the player is unsuccessful in regaining the full amount of energy, the character is considered to be "KO'd" and loses the match. Each successful match awards the character with Dwarven reputation points. Norn Fighting Tournament : The player character enters a tournament sequence of six matches, with the final match being against Magni the Bison (a reference to M. Bison of the Street Fighter series). Victory in the tournament awards Norn reputation points, certain prize items, and championship tokens that are redeemable for trophies such as crowns. Polymock : Resembling Pokémon, the player fields a team of up to three "pieces" against his opponent's team. Each piece morphs into a specific creature with a set skill-bar and predetermined weaknesses and resistances. Prior to beating Hoff, the Polymock master, victories award Asura title track points, a polymock piece and sometimes an Asura title track spell. After beating Hoff, for the Mirage Iboga piece, victory in Polymock matches merely awards Asura title track points.
Eye of the North is set eight years after an event known as "The Searing" occurs in Guild Wars: Prophecies, where a northern race of cat-like beasts known as the Charr incinerate the Tyrian kingdom of Ascalon. Earthquakes begin to increase in frequency across all the three continents of the game world; Tyria, Cantha and Elona, which correspond to the three Guild Wars stand-alone campaigns; Prophecies, Factions and Nightfall, respectively. Strange creatures have begun to emerge from crevasses created by these earthquakes and the player is tasked to investigate further, starting from either Lion’s Arch, port city of Tyria; Kaineng Center, port city of Cantha; or Kamadan, Jewel of Istan, port city of Elona.
Descending into one of these crevasses the player fights enemies native to the respective campaign before coming across a Dwarf named Ogden Stonehealer and an Asuran named Vekk – a race unknown to most humans that have only surfaced due to the earthquakes. It is not long before the party is ambushed by a group of creatures known as "Destroyers". The party then makes their escape through an Asura Gate (a teleportation device similar in appearance and function to ones seen in Stargate) which brings them into the Far Shiverpeaks. Vekk destroys the gate to ensure the Destroyers have no chance of following them. It is here that they meet a Norn (a race of giants that resemble the Vikings in terms of culture and appearance) named Jora. She tells the player of the existence of humans in the Far Shiverpeaks and Ogden, Vekk and the player eventually make their way north to a huge structure called "The Eye of the North". It is here that they come across Gwen, a character that first appeared in Prophecies as a little girl in Ascalon, prior to the "Searing". She informs the player of her temporary appointment as leader of the "Ebon Vanguard" (a group committed to fighting the Charr) in absence of an officer named Captain Langmar.
The player enters the Eye of the North and discovers a room called the Hall of Monuments. Upon approaching a scrying pool at the centre of the room, the player triggers a vision which displays Destroyers working their way towards the surface. Shocked by the prospect of the Destroyers being so close to their goal, Ogden, Vekk and Gwen make their own separate pleas to the player in gaining reinforcements. Ogden suggests to get help from the Norn; Vekk suggests that his people, the Asura, are the best choice whilst Gwen believes that finding Captain Langmar’s squad in the Charr Homelands would most benefit the player. The player can choose to help Ogden, Vekk or Gwen in any order he/she so wishes but is required to gain the help of the Norns, Asurans and the Ebon Vanguard before proceeding further into the game.
Through the course of the game, the player receives three more visions through the scrying pool. One of them reveals that the main antagonist is a being known as "The Great Destroyer"; the arch nemesis of the Dwarven god, The Great Dwarf. Another reveals its location, which Vekk identifies as a cavern nearby the Central Transfer Chamber, a junction for the Asura Gate network. With the help of new allies secured, Ogden Stonehealer tells the player that they are required to head to the Heart of the Shiverpeaks to summon the Great Dwarf. Only then would the Deldrimor Dwarves stand a chance against the Great Destroyer. The player eventually meets with king Jalis Ironhammer to prepare for the final onslaught against the Destroyers, where he initiates a ritual that permanently changes him and the Deldrimor Dwarves by imbuing them with magical strength and transforming them into stone. It is then that the final assault commences in earnest as the Deldrimor Dwarves, the Norn, the Asura, and the Ebon Vanguard fight side by side to reach the Central Transfer Chamber. Upon arriving at the Central Transfer Chamber, the player conducts the final battle against The Great Destroyer. With his defeat, the world is safe once again.
The new features introduced by Eye of the North had a mixed reception. The three new mini games received good reviews, with GameSpy stating that they are "really well-designed and incredibly involving." Some reviewers criticized their unavailability in the player versus player mode of the game. The Hall of Monuments was considered by 1UP.com to be a "hasty advertisement for Guild Wars 2"; GamerNode suggested that it seemed to encourage a style of gameplay contrary to the original spirit of Guild Wars.