Invasion is an objective gametype that debuted in the video game Halo: Reach. It's most distinguishing features are that it has Elites battling against Spartans, squads, and that it also has three different phases of battle. In the Halo: Reach Multiplayer Beta, it is always played on the map Boneyard.
A unique feature to this gametype are squads. In both Invasion and Invasion Slayer, each side has three squads of two. When respawning, you may choose to either spawn on your partner, or you can spawn in one of the unlocked areas.
At this stage, the Squad system seems a bit redundant. Invasion and Invasion Slayer are set up so that games with a small amount of people in them can seem action packed at all times. Giving you the option to spawn on your buddy, but not when he's in the action, is painful in this gametype. 90% of the time your buddy will be in the thick of the action and you will have to spawn back in your own spawn point anyway. Hopefully they allow for larger squads in the finished product to allow for a better chance to spawn somewhere relevant.
In the Beta, there are two gametypes available for Invasion. Regular Invasion and Invasion Slayer.
 Regular Invasion
Invasion has three different phases of battle, each with varying objectives for each side.
 First Phase
The Elites must first capture one of two designated areas by remaining in them for the set amount of time, much like the gametype Territories. Doing so will result in one of the generators being shut down, allowing the Elites to move on to the next objective. Meanwhile, the Spartans are attempting to prevent this from happening. If the Elites succeed, weaponry is dropped in near the two generators, and the Elites are also given a Ghost near their original base, while the Spartans are given a Warthog.
 Second Phase
Once the second phase begins, each side is given superior classes to spawn with than before.
Much like the first phase, the Elites are once again presented with one of two areas they must capture, and the Spartans attempt to prevent them from doing so within the time limit. If the Elites succeed, each side is presented with more vehicles. Spartans are given a Scorpion, while Elites are given a Banshee and a Wraith.
 Third Phase
During this last phase, the Elites must pickup the data core and deliver it to the designated area near the hovering Phantom. Doing so will result in victory for the Elites. However, if the Spartans manage to do prevent them from delivering it within the time limit, the Spartans are then given the victory instead.
 Invasion Slayer
See main article: Invasion Slayer
Invasion Slayer, while still a traditional Deathmatch, has a bit of a twist. Invasion Slayer comprises of 6 v 6 gameplay, Covenant v Spartans, like Invasion. The twist being that there are territories on the map in alternating locations, which can be captured by either team. It takes 10 seconds of occupation to capture the points, and the only thing gained by which team captures the point is what kind of reinforcements are dropped. If the Covenant team capture the point, you can bank on either a Ghost, Banshee or Wraith as reinforcements. If, however, the Spartan team take the point, you can expect either a Warthog, Scorpion tank or a weapons drop of a Sniper Rifle and a Rocket Launcher. It takes a further 12 seconds for the reinforcements to be dropped after the point is captured, leaving the supplies open to enemy pilfering.
The phases in Invasion Slayer are much simpler than the Phases in Invasion. The game is made up of 4 phases, each phase comes after 25 kills for a team, so each team earns their phases at different times. The phases in Invasion Slayer are simply loadout progression. Both teams starting with the basic weapon and a grenade. Phases 2 through to 4 unlock progressively stronger weapons, which leads to out and out mayhem towards the end of the game when every elite can spawn with a sword and every Spartan can spawn with a Grenade Launcher.
'Note: It's important earlier on in the game to focus on the territories and weapon drops. With the weaker loadouts at hand, it's always preferable to have a vehicle or two on your side. Or some extra firepower in the Spartans' case.
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