Tips for legendary campaign without any exploits:
Turn Catch and Tilt skulls on.
Tilt makes weaknesses and strengths even more intense. It’ll make the Plasma Pistol / Needle Rifle / Needler / Plasma Nades stronger. Of course it’ll make the DMR/Pistol weaker but I consider it a good trade off, as it still allows for the DMRs primary function of finishing off unshielded opponents with headshots. So basically it makes all the strong enemies weaker, but makes the weakest of all enemies slightly stronger. I’ll take that deal every time.
“Catch” of course means more plasma nades for you to collect off of dead bodies, but you need to keep your distance so you don’t get stuck as well.
A big tip is to reduce the amount of guns firing at you. If you see an Elite with a group of grunts, yeah if you kill the Elite the grunts tend to scatter, but on Legendary that’s a rough way of trying to get through the level. Take out grunts first with headshots, then you’ll be left with the big guys. In a 1v1 fight they are a lot easier to kill. Remember that ANY enemy can kill you, so clearing out all the small grunts first really decreases your opponent’s DPS.
Keep your distance from the big guys. If an Elite is using a plasma weapon the projectile speed is significantly lower than what you’ll be using. The farther away you are, the more likely it’ll be for your strafe to avoid the damage.
Juggle weapons. Each time you switch out a weapon it’ll throw the one you dropped a few feet forward. You can therefore constantly switch and be “Juggling” 3 weapons at a time.
The drop shield is the AA of the Gods on Legendary. Using this bad boy will regenerate the health of anybody inside it, incredibly useful on legendary
Take advantage of AI. If you’re in a Warthog give the AI in the passenger seat a heavy weapon like the Rocket Launcher. They’ll have infinite ammo and having an anti-vehicle weapon along for the ride makes it a lot easier to handle covenant vehicles.
Take enemy Wraiths whenever possible. Headshot the gunner out, use the Plasma Pistol to EMP it, KEEP USING EMP as you approach from the SIDE, until you’re in position to hijack it. Board the wraith, punch off the hood, dismount, EMP again, JUMP on (Not with the board/hijack button), then melee the driver to kill them. Now you have a wraith. This bad boy makes short work of anything else the enemy has (Not scarabs of course lolz)
If you’re doing coop campaign, you can kill your teammates in order to regenerate ammo. My teammates and I kill each other all the time to keep our nades and ammo supplies full for each fight. Additionally if a person is low health after a battle it is a quick way of replenishing it lol.
Let the AI do most of the work. At times you’ll see your allied Spartans just going to town on enemy Elites, but taking forever to kill them. Just wait for the Elite’s shields to drop and finish them off with a headshot.
Always fight groups from as far away as possible. If you can stay far back and reduce the enemy’s numbers with your DMR/Sniper before moving in, it is far better than trying to run in with a hammer/shotgun/sword and clearing the group.
Patience is a virtue. Nothing wrong with killing 1 enemy, letting your shield recharge, then repeating 20 times before you can move on.
You WILL die. I’ve ran hundreds of missions on Halo 3 / Halo Reach on Legendary. I know every trick in the book and I still die. Just keep your cool and don’t let it get to you.
Switch tactics. If you keep dying on the same part repeatedly, analyze the situation, switch up the direction you attack from, switch weapons, etc. Different encounters require slightly different tactics.
Spawn kill. Sometimes you’ll see a Phantom dropping off enemy covenant. Killing them as the hatch opens up, when they drop off, and when they first hit the ground is a great way to reduce their numbers without them being able to fight back.
Spawn Anchor. You can set up a guest controller and have it just stay in cover. Fight with your main controller. If you die, respawn and go kill more stuff. Repeat until every enemy is dead lol. Don’t try this on Tip of the Spear as the Falcon ride will get you slaughtered.
Elites- Plasma Pistol EMP then Headshot is best. Needlers work too but only fire off like 3, they’ll go into their BS Armor Lock, then once they exit launch the REAL needle barrage. They are best fought at mid range rather than close (Unless you’ve obtained a sword)
Jackals- There is a small gap in the shields where their hands are. Shoot the gap with a DMR to stagger them, then follow up with a quick headshot to finish them off. Additionally the shield can be EMPed off with the Plasma Pistol
Grunts- If in a small enclosed space grenades are incredibly useful. Mostly try to finish them off with headshots
Brute Chieftains with Hammer- Amazingly pathetic and easy to kill with. When they charge you RUN AT THEM! Once they begin their hammer swing simply jump right over them. How they became chieftains is beyond me because they flat out suck
Brute Chieftains with Fuel Rod- You’ll have to EMP them multiple times before their shields drop. Keep your distance and jump strafe as much as you can to avoid the fuel rod
Drones/Buggers- I never fight them, I activate the event trigger, grab camouflage and just run back to the elevator lol.
Hunters- No real cheap way of ending them. If you know they’re coming up try to have a heavy weapon ready. If you can hit them in their unarmored backs it’ll do more damage, I think they’re weak vs plasma but I could be wrong. Mostly it is about coming prepared.
Sprint- Unless you have a Sword/Hammer isn’t that great. Mostly to break combat, but if you’re fighting at a distance near cover it isn’t an issue anyway.
Camouflage- Great against buggers but outside of that is lame as the cheap AI will most likely target you anyway.
Armor Lock- You may have been able to fool inexperienced casual players in matchmaking, but don’t expect the same results in campaign. You might have some success with shotgun/frost/shotgun in CQC but honestly I wouldn’t even bother with AA. Seriously.
Jetpack- My AA of choice in multiplayer matchmaking. In campaign can be used to finish Exodus early by jet packing up to the final switch and thus skipping a group of strong enemies. Also useful for skyjacking enemy banshees on Tip of the Spear and The Package
Hologram- Amazing, the AI could watch you throw the hologram and would still fall for it. Spam the hell out of this thing. I cannot express how useful this is.
Drop Shield- Easy way to break combat, and replenishes your health without using up a health pack. My AA of choice on Legendary.
Best of luck to you TC.