Halo: Combat Evolved Anniversary

Ok this one can be very frustrating as you won't get the achievement until you get into the banshee. most of the elites are on the path you follow but there are some hiding off the path. i would highly suggest you use the bandanna skull.

here's a list of all the elite spawns i've recorded.

1)Two elites fighting across the jump down.
2)After the jump there will be 2 i believe fighting flood.
3)Next pack along there is 2 more.
4)With the pack that has hunters in them are 3 elites.
5) Next one along is in the turret.
6) 3 elites fighting at the top of the grav lift, you must get all 3 before going up.
7)Down the path you will come accross 2 elites
8)next 2 are down the path you must follow, you will get ambushed by flood afterwards.
9)4 Elites are across the platform surrounded by shields and a turret take them out.
10) When you reach the point where the 4 elites where mobs will spawn both sides, i spawned them 4 times and then did step 11 which then stopped them from spawning.
11) this step can be done later but i did this beforehand, if you go down the path the covenant was spawning and follow it you will find two more at the bottom.
12) on the 3rd floor a drop ship will come in and a elite will appear on the middle platform take him out and continue.
13) 2 elites will be fighting flood just before you reach keyes.
14) 2 or 3 more elites will show after you get the implant from keyes.
15) 2 more elites will ambush you as you make your way to the banshee.
16)Follow the intended path down to the banshees and you will run into another one.
17) should be 3 or 4 elites with the banshees kill them all.
18) there's another 2 in the back tunnels you will find
19) sometimes ive had 2 extra spawn on a few playthroughs if this happens they should appear around the banshee area. on easy they didn't show

After you have done this another group of elites should spawn kill them off then use the banshee. if done right it should pop, i would go in more detail but i didn't figure i would get them all.

Let me clarify Quickdraw1988's guide:

There are three area's in this level, the first two have missable Elites:
-The first section on the Covenant Cruiser (Elites are missable)
-The cooling liquid pools area on the ground (Elites are missable)

Everything after the Grav Lift is not missable. Follow a few steps below and you should be alright:

- Use the Bandana skull for infinite grenades and sniper rounds (you will get the sniper just before the grav lift, it will help kill spec-ops Elites quicker. Specifically the Sniper is on the last bend before the opening to the Grav Lift area. You would be extremely unlucky if you managed to miss this)
- If Elite's die before you get a chance to kill them, it counts as one of your kills.
- The two Elites at the start on the Covenant ship (on the opposite side of the large hole you fall through) count towards this achievement.
-Spec-Op Elites infinitely respawn in the Banshee hangar bay. They also hide. Cover all the floors and all rooms from top to bottom, then bottom to top and a third time on the way down to be sure. I have found 2 or 3 Spec-Op's in hiding when I did this. This will also stop the inifinite respawn of the Spec-Op Elite's in the Banshee Hangar.

Unfortunately I no longer have a capture card so am unable to record this for everyone but as a rule of thumb, extensively cover the first section when you are on the Covenant Cruiser and also when you fall into the cooling liquid pools on the ground of the level. Every other Elite will be easy pickings apart from the first two areas.

The only really tricky part of this achievement is at the very end right before you get into the Banshee. You will need to search through *all* the corridors to make sure you didn't miss any because there are a lot lurking around in places you probably haven't been. Be sure you pick up the sniper rifle near the pool with the infinitely spawning Flood carrier forms because it will come in handy when you are hunting Elites.

The achievement won't unlock until you get into the Banshee.

this acheivement can be done in co-op. i did it by using my wifes account as a spawn dummy and when mission ended both accounts got the acheivement. just to let anyone else tring to do it try it on co-op might make it easier for you.

As everyone knows: A Video says more than 1.000 words!
Found this Guide on YouTube I hope it helps

But it shouldn't be that of a problem just kill everything thats moves.
And you can also go for the Popcorn.Gif Achievements as well.