It is based during the time that Master Chief is entering the atmosphere of Earth at the start of Halo 3. The ODST's must get the laser designator and tag the chief before he hits the ground so Johnson and Arbiter can locate and retrieve him.
Kept under tight wraps, the set was announced unexpectedly on July 10, 2007 with the release of the first video, Halo: Arms Race on the front page of Bungie.net. Arms Race featured several shots of characters as well as special effects and set props, but little real action. The film was also shown at E3 2007, and with it came promises of additional shorts.
Arms Race was a live-action trailer that went up with another film one long month later. Combat, released on WETA's website in August 2007, telling the story of two ODST troopers fighting off Brutes while trying to retrieve an object - later revealed as a targeting laser - on the battlefield during the Battle of Earth.
A third film, Last One Standing, was released on September 24, just hours before the release of Halo 3. This film was released first on the Discovery Channel's website, as part of their promotion for an unrelated show, Last One Standing. This film continued the story of the two ODSTs in Combat, featuring more weapons, special effects, and live-action combat between the Marines and Brutes. A few Marines are killed, but take many Brutes down with them. It ends with the sight of a fireball descending into the atmosphere, a scene which is also the beginning of Halo 3, which explains how the UNSC was able to predict where John-117's landing would be, as the mission was to affix trajectory on his descent using a laser-guided tracker.
On October 26, 2007, all three films were edited together into one seven-minute mini-movie, and were released simultaneously on Bungie.net and Xbox Live Marketplace. The mini-movie is titled Halo: Landfall.
- The achievement for finishing the first playable level of Halo 3 on normal or above might be a reference to the title.
- In the cutscene in-game, when Master Chief falls to Earth, it is night, when in the video, it is clearly the morning at the very least. This is most likely due to the timezones, the location of the Master Chief's landing site and the area where Halo: Landfall takes place.
- The only enemies that are shown in the whole film are Brutes, wielding Spikers, and one Brute Chieftain with a Gravity Hammer. However, while they have Power Armor, when being shot they behave as though it is not there. Also, Banshees and a Phantom are shown but no other Covenant vehicles or species.
- The attacking Banshee shown at 05:15 has no cockpit, just the lower section and wings.
- All of the movies combined add up to a total of 7 minutes.