"Help with the evacuation of Alpha Base, and lead the marines to the Pillar of Autumn"
None Left Behind is the eleventh mission in Halo SPV3, added in the SPV3.2 update in 2019, along with The Commander, The Commander: Evolved and the Lumoria campaign. It is listed as SPV3D25, also known as D25. After the events of Keyes, the Chief pilots the stolen Banshee from the Truth and Reconciliation back to Alpha Base, after recieving a distress call from Avery Johnson.
Overview & Background
The mission involves fighting through Covenant, Sentinel Enforcers and Flood to Alpha Base, where a bunch of Marines are trapped and undersiege from the Flood. After assisting them, Cortana opens the bases main gates so that the Chief, along with the Marines, can escape to a Pelican in the spot where the Chief first landed on Halo. However, the mission is doomed to fail due to the overwhelming numbers of Flood and the appearance of Sentinel Enforcers. Only the Chief and Cortana make it.
Sheila Polaski, the pilot of Echo-205, is featured again, her second and final appearance in SPV3 as a guide for Chief and Cortana and adding exposition for players.
This mission reuses the level design of the second mission, Halo, except it is played in reverse. In juxtaposition of its counterpart level, None Left Behind is set at night and has gone from a flourishing greenland to a war torn landscape surrounded by forest fires that have filled the air with smoke and ash, making visibility poor.
The Blind Wolves that were in previous missions, make another appearance here, only this time, they have been infected by the Flood. They are armed with natural projectiles seen on the Ranged Pure Flood Forms in Halo 3 and act as Combat Carrier Forms, releasing Infection Forms when killed.
- A beta of None Left Behind was going to be released but was cancelled due to the SPV3 team working on project "Oddball." The level has since been released alongside the SPV3.2 update.
- During the final portion of the mission, the bird songs heard in the mission Halo can be heard, despite the environment indicating that there would be no birds there.
- This mission, along with 343 Guilty Spark, are the only missions that feature Marine versus Flood combat.
- The mission features dialogue for Cortana and Avery Johnson that has been taken from other parts of the game, other games in the series and even unused lines that were never featured in any of the games before. The voice of Sheila Polaski was done with a voice actor specifically for use in Halo SPV3.
- Although the narrative of the level implies that all Marines are killed during the mission, it is actually possible to save some Marines, albeit not many, from the massacre at Alpha Base and from the final stand at the Pelican at the end of the level. However, the Marines at Alpha Base will not follow the player into the tunnels, and the Marines at the end will not board the Pelican and will be left behind, though the dialogue will still play out the same.
- Due to the Chief's escape on the Pelican at the end of None Left Behind, the intro cutscene of The Maw has been changed to show the Chief flying a Pelican, instead of a Banshee like the original Halo CE.