Halo: Combat Evolved Anniversary
44 Achievements
1,000
15-20h
Grenadier
Escape the map room in “The Silent Cartographer” without firing a shot on Heroic or Legendary.
25
How to unlock the Grenadier achievement in Halo: Combat Evolved Anniversary - Definitive Guide
Also there's a over shield outside the map room to boost your health. and med packs half way back up, you should pass them on your way in leave least 1 for later.
Note; not my video, I take no credit, just passing it along.
1. When entrering the complex, check if you still have a Wartog available. Head back to the start of the level. There should be a squad of marines waiting. Let 2 marines join you, so you have a gunner and a passanger on the Warthog. Then drive as far as possible into the complex with them (this is in front of the gate you have to open before) and park it facing towards the exit.
2. When worked your way down the complex, clear the area from all enemies and memorize the shortest way back to the exit.
3. DON'T PICK UP the cloaking device YET. Save it until you until you go back up. But watch out, when you want to pick it up, there are 2 jackals waiting. Melee them down, because if the jackals are still alive when you pick up the cloaking, the enemies can see you.
4. Also watch out on your way back up that you dont touch any enemy. Otherwise they get suspicous and eventually notice you are there. When the cloking runs out, the rest of the way to the Wartog is simple running and dodging. You should have enough shield + energy to survive until you reach the Warthog.
5. Once back in the warthog drive back up to the exit and wait until the covenant vessel has gone. The marines will shoot the cloaked Elites. Board the Pelican when it arrives and you are done.
If you happen to fire a shot (I had the magnum), just revert to last save, and all is forgotten. You can die as many times as you like.
As in other solutions, make sure to clear everything out first, especially the Hunters. They don't go down by grenade spamming them. You have to expose and shoot them in the back.
As for strategy, well, take your time, grenade spam and hide, rinse and repeat. I used a lot of doors and threw in grenades as they opened to clear a path. Bandana skull, of course, is a must.
One thing I found odd was that I blew by the first set of Hunters (on the outside) on the way to finding the security override for the map room. When I came back to clean them up, it seemed a bunch of Elites were waiting for me instead. I guess they didn't take kindly to me getting past them. :) Again, shoot the Hunter in the back in his exposed area, he will go down in a couple of shots.
Maker sure you're fully stocked on Frags and Plasmas before you go down (there's a cache of frags on the floor with the hunters. The elites on the bottom floor should drop plenty of grenades as well.) Assuming you killed everything before activating the map, there should be no enemies on this floor. On your way up to the next floor, you’ll be stormed by 2 jackals on the rampway. Usually a frag makes good work of them. After leaving the ramp room, a door to the right will lead down another ramp and a camo should be just at the exit. Use it and you can easily bypass the entire floor - just make sure you beat down any pesky elites you run into on your way. On the next floor you’ll have an elite and a few grunts. A frag is good for that followed with a melee to put the elite down for good. Go up the final ramp to the top floor and immediately to your right will be your exit blocked by an elite. Pop a grenade in there and make a run for the tunnel (if he doesn't die, he shouldn't follow you.) Go around the next turn and you'll be blocked by a Gold Sword Elite. As he taunts you quickly stick him with a plasma grenade. All you have left now is a few invisible elites at the very top of the structure. Lure them over one at a time and beat or grenade them to death and you’re path to the pelican will be open!
Grenade Jump trick: IF you're any good at grenade jumping, instead of going up to the second floor from the map room, there will be a small room across the way. Two jackals will be on the platform above. Take them out with a grenade, than grenade jump up and you'll be right next to the aforementioned camo pickup. This is a good way to prevent the entire room from being alerted.
Note: If you've got it, Grunt Funeral skull is excellent for this scene because a single frag can set off a decent chain reaction of grunts if time it right.