Halo 2/Gameplay

Campaign
The game is playable in campaign mode either single-player or cooperative. This mode follows the story to the Halo series and is the second of the three games (the third and final part of the series is still not published). When playing in this mode the player(s) must complete a series of episodes. Some of these episodes require the player to compete as a Covenant Elite called The Arbiter, while some, but not the majority are still played as the Master Chief. Aside from variations caused simply by switching sides in the conflict, most notably The Arbiter is different from Master Chief in that his armor lacks a flashlight and is equipped with a short duration rechargeable form of active camouflage that will drop if the player attacks or is shot. His shield is also weaker than the Master Chief's - probably a result of its age. Another possibility is that the Arbiter was designed to be less of a battering ram than the Master Chief, which subsequently requires different tactics. Additionally, the story line while playing as the Arbiter changes to one of fighting an internal faction within the Covenant, with the elites, hunters and grunts forming one team and the brutes, jackals, prophets and drones forming the other.

There are four levels of difficulty: Easy, Normal, Heroic and Legendary, the latter of which has been described as "suicide" by the game's developers. An increase in difficulty will result in an increase in the health of opponents, an increase in their accuracy, and a reduction of health in the player.

Multiplayer
There are varying modes, several of which have returned from the original Halo game. A typical classic free for all or team deathmatch game known as Slayer, a team based Capture The Flag game, a game which you plant a bomb in your enemies base to score called Assault, a more esoteric free-for-all (FFA) or team game of keep away called Oddball, a game extrapolated from a child's game of "tag" called Juggernaut, King of the Hill, where players race to control a specified area of the map, and finally, Territories, which bears some resemblance to King of the Hill, but with multiple hills. All of these modes can be twisted and changed in thousands of unpredictable ways, resulting in incredibly varied multiplayer gameplay. Of the preset variations present in the original game, only Race is missing.

Unlike its predecessor, Halo 2 allows players to compete with each other via the Xbox Live online service, in addition to the original's support for split-screen and System Link multiplayer. Halo 2 ' s Xbox Live mode offers a unique and, some would say, innovative approach to online gaming that is intended to alleviate some of the problems that have plagued online first-person shooters in the past. Traditionally, one player sets his or her computer or console up as a game server (or host), specifying the game type and map and configuring other settings. The game software then uses a service like GameSpy to advertise the game to the world at large; other players choose which game to join based upon criteria such as the map and game options each host is offering as well as the ping times they are able to receive.

In Halo 2, Xbox Live players do not choose to host public games, and they do not get to specify individual maps and options to search for. Instead, players select "playlists" that are geared to different styles of play. For example, the "Rumble Pit" playlist offers a variety of "every man for himself" game types, primarily Slayer or variations thereof; "Team Skirmish" offers a number of 4-on-4 team games, which are primarily objective-based games like Capture the Flag; "Big Team Battle" is similar to Team Skirmish but allows teams of up to 8 players. Other playlists allow head-to-head play and matches between different clans. The Xbox Live servers create games automatically from the pool of players that have chosen each playlist, choosing a game type and map automatically and selecting one player to serve as the game's host.

Players can create small "parties" with their friends and enter games together as teammates in Team based games. Parties can also play in "Rumble Training" games, which is an unranked version of "Rumble Pit" If the Xbox console hosting the game drops out, the Xbox Live service automatically selects a new host from among the remaining players so the game can continue. Players may still choose to set up games for their own party to their own specification, and invite others into that game from their Friends and Clan lists, however these games are not made publicly available.

Bungie.net records every single statistic that is displayed on-screen in the end-of-game "Postgame Carnage Report." Anyone can visit Bungie.net and look at any Xbox Live player's stats. If a player logs in with a Microsoft Passport, they can also access the "Gameviewer". This presents an image of the level that was played from the player's choice various angles, superimposed with a summary of the crucial game events. For example: for each kill, the attacker and target's locations and the attacker's weapon are displayed, and the paths taken by flags in Capture the Flag games are shown. Bungie keeps these stats for several hundred games per player at a time, then games begin to be purged to save space, and they are used as evidence when banning suspected cheating players (see "Xbox Live Updates", below).

Regular players have expressed concerns regarding the game balance of Halo 2. Many players feel that game strategies are too dependent upon controlling the "power weapons" in each map such as the Rocket Launcher, Sniper Rifle, Shotgun, or Energy Sword, which leads to the overshadowing of the other weapons in the game. Should a team acquire these weapons, it becomes more difficult for their opponents to score kills or attain objectives. Much game time may be consumed attempting to seize the weapons in question from the opposition to shift the balance of power; in some cases it may not even be possible to do so. This primarily affects team games and one-on-one games; in free for alls, a player with a "power weapon" will become a priority target for the other players, meaning that the weapon will change hands frequently. Another common criticism is the dominance of dual-wielding weapons over single-wielding combined with grenades, although attempts have been made to address these issues with the April 18th automatic update.

A second mode of Multiplayer is also available called "Cooperative", in which two players on the same console can play through the singleplayer campaign together. Both players share the same character model (i.e. two Master Chiefs or two Arbiters) and the addition made by the second player does not change any events in game. When one player dies in Co-op, he or she is given a birds-eye view of the other player, and a small line of text displaying the condition for the living player to fulfill for the deceased to respawn, for example "Too many enemies nearby" would mean that there are too many enemies around the living player to have the other respawn, and he must retreat to a safer area. however, on the Legendary difficulty, when one player dies, the game is reverted to the last checkpoint. Unfortunately, the Co-op game mode does not work on Xbox Live.

Damage system
The damage system in Halo 2 is slightly different from that in Halo: Combat Evolved. The player has a regenerating shield, but now has regenerating health as well.


 * Shields: The shield in Halo 2 is much stronger, and recharges at a higher rate. It covers the player's entire body, and slowly decreases in power as it sustains damage.  After it takes damage, it starts to recharge 4 seconds after the last time damage was sustained.  The power is displayed above the motion tracker in the bottom-left of the screen. Like in the original Halo, once the shields become low an alarm informs the player that they are out.
 * Health: In Halo 2, once the shields run out, the player also has a buffer of health. Unlike the first Halo, health regenerates after the shield.  The amount of health left is not visible to the player, and is also much smaller than in the original game.