Setting up

Roadmap

Even if you normally play Halo on Legendary, take my advice and use Heroic or lower for this battle - at least until you know what you're letting yourself in for!

Start off with the basic plan. It won't give you any Marines, but it's relatively simple and will get you used to the way things work, and you'll still get plenty of great combat from it. There are more set-up tips on a separate page, to help you get the most out of things.

When you've had enough solo battling, move on to the business of Marine support. It takes a lot more work to set things up, but it's worth it. You'll find that I give two plans there; one for giving you a small squad, and a more complicated plan for a large squad. Both plans include a description of how to create a good base save that covers the bulk of the work, making it easy to then produce multiple finished battles featuring different squad arrangements and so on. That's definitely the way to work.

Enemy numbers

I think I'm safe in saying that this battle is the biggest available in the entire game. On Legendary you can get an amazing 90 enemies, on Heroic 79, and on Normal or Easy 75. You won't necessarily want such high numbers though, as the accompanying framerate slowdown can degrade the battle experience quite a lot, especially when a lot of enemies are close up (thus having to be rendered in more detail). It should also be mentioned that when battling alongside a large squad of Marines, you'll normally have killed most of the enemies that spawn in the twin bridges area, to ease the set-up work. However, here's a full breakdown.

Enemy breakdown

Expressed as 'Elites + Jackals + Grunts + Hunters', the potential number N of enemies breaks down as follows:

  • On Legendary, N = 29 + 18 + 39 + 4 = 90.
  • On Heroic, N = 25 + 13 + 37 + 4 = 79.
  • On Normal or Easy, N = 25 + 11 + 35 + 4 = 75.

As for where they all come from, I'll break them into two groups. From before the twin bridges area we have the following (68 on Legendary, 59 on Heroic, 56 otherwise):

  • Enemies for the spiral path megabattle (61 on Legendary, 53 on Heroic, 50 otherwise).
  • 2 Shade gunners in the spiral path area.
  • 2 underpass Hunters spawning with the spiral path Marines.
  • 1 cloaked underpass guard, or 2 on Legendary.
  • 1 Shade gunner on the underpass roof.

And from the twin bridges area itself we get the rest (22 on Legendary, 20 on Heroic, 19 otherwise):

  • A squad at the start: 2 Elites plus 5 Grunts on Legendary, 1 plus 4 on Heroic, else 1 plus 3.
  • A second squad further back: 1 Elite plus 4 Grunts.
  • 1 Shade gunner for the platform Shade.
  • 2 Ghost pilots and 1 Banshee pilot.
  • 2 Shade gunners near the door.
  • 2 trough passage Elites.
  • 2 door Elites.

As in the spiral path megabattle (and throughout the game I expect), the split between nasty red Elites and the softer blue Elites is randomized but with a possible bias one way or the other. Legendary has a strong bias towards reds, Heroic shows no obvious bias either way, Normal shows some bias towards blues, and Easy has a strong bias towards blues.

Probably a few less in practice

With a decent amount of effort you can certainly get close to the maximum in practice, when creating a solo battle or one with a small squad of Marines. However, you can easily lose a few enemies from friendly fire when trying to tempt them through the underpass. That's partly down to how idiotic the Covenant are feeling today, but you can minimize losses by being thoughtful and patient. I've got everyone through ok on Heroic at least once, and on Normal I've lost as few as two minor enemies there.

Free-roamers and territorials

In the battle, all enemies that came from earlier areas seem to be free-roaming, i.e. free to chase you about. So are some of the enemies triggered in the twin bridges area, but others are limited to their own particular territories when on foot - at least initially. You might want to eliminate territorials, as they usually won't be playing a part in the main battling, yet they'll still be a drain on the game's processing power and thus be contributing to framerate slowdown. Also, maybe you simply don't want them left over to deal with after the main fighting (though they can provide a nice leisurely way of finishing off).

There seem to be ten covies who are either initially or permanently territorial. Namely, the second squad (an Elite and 4 Grunts), the Ghost pilots, the Banshee pilot, and the door Elites. However, if you kill any three guys in that second squad, the remaining two become free-roaming. If you want to eliminate any territorials (e.g. eight of those ten, leaving two of the second squad to become free-roamers), the best time to do most of it is before enemies have come through from the spiral path area. If you're not quite sure who's who, just see who follows your Banshee, and you'll know those are free-roaming.

Grunt gaggles

If you're interested in having a huge gaggle of Grunts chasing you around, on Legendary you could get a gaggle of 37 if you convert two Grunts from the second squad into free-roamers (note: territorial Grunts wouldn't count as part of a gaggle as they'd be logically separate, even though they could sometimes be near the free-roamers). On Heroic you could have a gaggle of 35, and on Normal and Easy 33. I believe that the 37-strong gaggle on Legendary is the largest gaggle in the game!

Getting a delayed tunnel checkpoint

Throughout the later stages of creating a battle, there's always the option of going back to trigger a tunnel checkpoint which you can then delay with Banshee fire until you return, getting the checkpoint in some desired spot. This can be a good idea before a tricky bit of work, so that if things don't go well enough, you can revert for another go without losing earlier work; and so that you'll be able to make repeated attempts with minimal delay. But there are a few things to keep in mind.

Rock geometry gets randomized

Rock geometry will get randomized afresh, namely as you cross the loading point on your return from the triggering. This may or may not be important to you at the present time. The main two occasions on which you'll potentially be interested in rock geometry are (1) when you plan on getting Marines into a pen by backing a hog over a conveniently low rock, and (2) when getting the final rock geometry for your battle (e.g. you might like certain rocks to be low enough to shoot over).

Keep Marines away from the enemy

When you fly off, make sure no Marines are going to follow you far enough to start tangling with enemies in the spiral path area. Typically you'd have the underpass exit blocked with a Ghost to stop Marines coming back through. Actually though, it also suffices to lead them into the back half of the twin bridges area before flying off. They won't chase far; they stop once you're sufficiently distant.

Marines may lose awareness of you, but there's a fix

When you get back to the Marines, you may find that they've strangely lost awareness of you. As part of that, they're not interested in boarding a hog - which would usually prevent you being able to pen them. They won't even dive clear if you drive a hog at them; it's like they simply don't see you or the hog, although they're still drawn in your direction. I suspect all this is a glitchy side-effect of going back through the loading point and returning. Fortunately however, there seems to be an easy fix. If you briefly get the attention of the enemy (probably now behind a blockade in the spiral path area), that seems to do the trick, and you can now pick up Marines in the hog if you want. I often make a point of getting the attention of the enemy as I return. But try not to give Jackals too big a shock, as they tend to let off involuntary blasts which can kill or damage their colleagues. Admittedly it's always hilarious to see a Grunt go down from a stray plasma ball, but here you want to keep your enemies alive for the later battle.

Ditto with trough passage Elites

I experienced something similar with the two trough passage Elites. After penning the Marines, I went to get a tunnel checkpoint so I wouldn't lose my penning work if anything went wrong later. When I returned and triggered the passage Elites, they didn't seem to know I was there, even if I went right up to bop one on the nose and shout "Yoo-hoo! Cyborg in town!". I was unable to lure them my way, and one of them started getting drawn towards the Marines. Bad news! But I found that if I took a moment to get the attention of the spiral path enemies on my return, this trouble didn't occur.

Possible enemy disappearance?

There was one time when I'd assembled a particularly huge crowd in the twin bridges area on Legendary (mainly as an experiment), and had also lured a Hunter along from the cavern to see if I could get him to participate in the battle (it didn't work). I flew back for a tunnel checkpoint, but returned to find that all the enemies had vanished! I suspect that the disappearance occurred at the loading point. But whether it was due to the game deciding it was under too much strain with the masses of enemy, or whether it was something to do with having the Hunter along from the earlier load zone, I don't know.