Halo Wars announcement trailer
From Halopedia, the Halo wiki
The trailer begins with an Ensemble Studios logo, before showing four M12 LRV Warthogs and two turretless Warthogs leaping over a rise in a snowy night landscape. The camera shifts to the two Marines in the lead Warthog, dressed in arctic uniforms.
The Warthogs catch up to an outfit of five M808B Scorpion tanks (Blue 5). The camera then pans ahead to two members of the recon patrol. The two seem to have re-established contact, as they radio in to Blue 6.
As they flee from an unidentified figure towards a waiting Warthog both Marines are promptly gunned down by plasma fire. The Passenger gasps as he hears it over the radio. One recon Marine is shown to have survived and is attempting to crawl away. He then turns on his back and witnesses an Elite uncloaking and drawing an Energy Sword. The passenger listens intently as screams are heard over the radio.
It is revealed that the last remaining patrol member has been killed. The Elite picks the Marine up and inspects him, letting out an animalistic snarl. It then tosses the dead Marine aside. Additional Elites uncloak behind him as eleven Banshees rise into the air and charge forward. An all-out battle breaks out as several Herons land, accompanied by Shortswords, Scorpions, and Warthogs. A group of Banshees is shown wreaking havoc upon the UNSC air forces, while several Marines taking cover behind an overturned Warthog gun down the leader of an Elite lance using what appear to be Battle Rifles. A Banshee strafes them, hitting one Marine and sending him flying into the camera.
The camera then cuts to an over-the-shoulder view of a Spartan. Several columns of smoke are seen rising from the destruction. The camera then flips and pans back revealing five Spartans standing in front of what appears to a platoon of Marines.
Four Shortswords fly overhead.
The screen cuts to a Halo Wars logo.
Music in the Trailer
The music begins with a restless violin section almost reminiscent of the music omnipresent the Matrix series. The music then shifts into a triumphant, driving drum beat that takes a distinctive minor turn when the recon team is gunned down. When the surviving recon soldier is stabbed with the energy sword, perhaps the most recognizable piece of music is heard: the Gregorian chant section of the original Halo theme song is reworked into a mournful section that depicts the hopelessness and despair of the fight against the Covenant. As the Elite tosses aside the body, the music takes a distinctive modal shift into what sounds almost Middle Eastern, but immediately shifts again into what sounds increasingly reminiscent of the beat-driven riffs of Martin O'Donnell of the Halo series, despite the fact that O'Donnell did not work on Halo Wars. After a desperate violin arpeggio, drum beats accent the brave words of Omega Leader, and the trailer ends with a simplistic low note that seems to be inspired by the simple tones of the Halo 3 Announcement Trailer.