Digging up the Past 20G In Mission 1, find and access Master Chief's record. There is a staircase on your right and left just as you leave the room with the stasis tank. Head down the steps to find a computer terminal (not a Terminal). Activate it for the Achievement, Digging up the Past. You'll get some backstory for your efforts and 20g. Midnight Launch 20G In Mission 2, get significant air in the Warthog at midnight. This odd Achievement can only be accomplished when your Xbox clock is set to 12:00AM (midnight). The easiest way to do this is to unplug your Xbox from the network and change your clock setting to just before midnight -- if you are removed from the network your clock won't automatically update. Set your clock to 11:53 PM to give yourself enough time to load up the level at Rally Point Alpha on any difficulty. Once you get your Warthog, stop just outside the tunnel area with all of the jumps. Wait for 11:59 to roll around (hit the glowing X button to bring up the menu and see your time) and count down to just before midnight using your preferred method (a watch, "one-one-thousand" etc.). At just before the clock rolls over to 12:00, start moving. The first few jumps probably won't get you a lot of air. But as you travel up hill, you will eventually hit a big jump and get the Achievement. Mission 3 20G This Is My Rifle, This Is My Gun. In Mission 3, carry a UNSC weapon all the way through on Heroic or harder. You definitely don't want to drop you Magnum here if you want this extremely tough Achievement. You'll have to keep it for the duration of the mission -- without even dropping it once! That means you'll have to use the Beam Rifle quite often and snipe from afar. This is MUCH easier on Heroic than Legendary. You have to get pretty creative with single weapons -- for instance, you can use Needlers on Watchers to easily explode them. Mission 4 20G Bros to the Close. Make it through Mission 4 without one preventable Marine death on Heroic or harder. After meeting up with the UNSC Marines in Mission 2, don't let any of them die. This video demonstrates how the Achievement works: Mission 5 20G Mortardom. In Mission 5, hijack a Wraith and use it to kill at least four enemy Wraiths on Heroic or harder. You'll want to aim for this Achievement on Heroic, not Legendary. To get Mortardom you do not have to kill the 4 enemy Wraiths with one single jacked Wraith -- you can jack a Wraith at the beginning of the level and kill 2 or 3 enemy Wraiths (around the large Covenant ship you destroy), then jack a different one at the end of the level (in the area with the Scorpions) and finish it off. To jack a Wraith, you'll definitely need a Plasma Pistol. It's best to take out the exposed Elite gunner before attempting to jack the Wraith, but not necessary. Try to approach the Wraith unnoticed or with cover between you and it. Hit the Wraith with a charged Plasma Pistol shot and it will shut down. You can only jack a Wraith from the very top of the tank. Here you will get a prompt to take out the gunner (in this case, shoot the Elite with the gun immediately) or to enter the Wraith itself. The area where you can jack the Wraith (and not just plant a grenade) is very small and looks like circular porthole. Once you have your Wraith, you can pretty easily take out others with two shots as you strafe back and forth. Again, you can take out a few Wraiths around the Covenant ship midway through the level (up to three), and then finish up your kill count at the end of the level in the Scorpion area to achieve Mortardom. Another Method After you have taken control of the first Wraith. If you proceed on until the Mammoth creates a bridge over the river. Drive around the Mammoth, and head forward towards the objective until "Checkpoint DONE" appears in the left hand corner on the screen, back track to the river and drive off the edge. You will spawn in an undamaged Wraith! After the 4th Wraith is destroyed only the Wraith driver will obtain the Achievement. Mission 6 20G Explore the Floor. In Mission 6, trick or force a Hunter to fall to his demise. To get Explore the Floor, you'll have to send one of the Hunters in the battle in the third spire off the ledge of the platform its on. The Fuel Rod Cannon you can obtain from an elite on the previous platform can help you do this, as will the explosive containers around the area. Basically, a series of explosions while a Hunter is at the edge of the precipice will send it over. It will take a few tries! On harder difficulties, the Hunters have more life, making them easier to blow over the edge. Mission 7 20G Give Him the Stick. In Mission 7 in solo Campaign, take out both Hunters using only the Sticky Detonator. The best way to take out the Hunters is by attacking their weak spot -- the lower back. The Sticky Detonator, found in both the office area and on a rack with Assault Rifles in the far corner, is the perfect device to take out the Hunters -- and you can get an Achievement for using it! Use your Hologram to distract a Hunter by sending it around a corner. When the Hunter takes the bait, stick a Detonator round on its rear. You'll need three Detonator rounds on Legendary to kill each Hunter, so be sure to restock at one of the two places mentioned above. Mission 8 20G Chief, Smash. In Mission 8, kill 3 Crawlers in one hit with the Gravity Hammer. Grab this Achievement on Easy. You'll come to an armory while jumping through portals in this Mission 8 -- several out-of-place weapons can be found here, including the Gravity Hammer suspended in an orange beam. The area after this features many, many Crawlers invading a spot you must defend. After you retrieve Cortana, you'll cross a bridge covered in Crawlers -- if you haven't got the Achievement yet, you'll get it here! Source - IGN. Complete Halo 4 Achievement List - XPG Link Spoiler http://www.xpgamesaves.com/topic/47250-halo-4-complete-achievement-list/#.UJqtKcVrghQ
