Halo 3: ODST

Complete the following achievements to unlock Xbox Live Gamerscore points.

Complete the indicated task to unlock the corresponding Avatar Award.

First of all, you need patience. If you don't, then just stop reading. You need to complete Coastal Highway. Wait until the credits are over (which will take a while). When the epilouge starts, start holding RS to the left. Keep holding it. When it should show the engineer lighting Sgt. Johnson's cigar, it will pan left and show Gunny "playing" with one of the monkeys from the monkey easter egg in Halo 3 Serria 117.

The 30th (last) audio file for Sadie's Story is not in the "Mombasa Streets" but rather in the "Data Hive" level (also played by the Rookie). However, it will be in a locked area until you find the 29 audio files in the Mombasa Streets. Once you find those files, play the mission "Data Hive" until you reach the hole to get to Sub-station 9. If you found the previous files, instead of the Superintentation closing off the hole so your cop teammate cannot get through (and ultimately get killed by Drones), he will climb down the hole with you. Continue playing until the cop says something similar to "Wait here, I need to go check something." Follow him and he will reveal his true purpose for coming here and will fight you. During or after the fight, you can scan the phone on the wall next to the dead body to find the 30th audio file. Note, finding the audio file will slightly alter the scene, specifically the part where DARE and the Rookie finds Vergil. Instead of DARE telling the Rookie not to shoot, the Rookie will tell DARE not to fire and instead whistle for Vergil to come out.

In order to take down an Engineer quickly, use the Covenant pistol. Fully charge it to take down Engineers with one shot. This applies to both Firefight, and Campaign modes.

Before boarding the Scorpion, hand your rocket launcher to any Marine riding on the tank. Note: For more mayhem, pick up the other rocket launcher from behind the tank and hand that off as well. Any kill the Marine makes counts toward the achievement. The Marine has unlimited ammunition, and will make getting the achievement much easier.

In Uplift Reserve, grab the Warthog at the beginning and load up with Marines. Shots fired from the Marines do not count, and you cannot use the e-brake or horn. Just fly through the level.

This achievement requires you to finish any mission under the Legendary difficulty setting with no shots fired. E-braking or honking the horn with the Warthog counts against you. Most players just pile a group of Marines into a Warthog and let them do all the shooting. The following method works slightly faster, and is a bit easier. When you get around the first corner from the starting point, there is a small battle going on with a Wraith and a few smaller Covenant vehicles firing on a squad of UNSC forces. Hijack a Ghost from that area and boost all the way to the end of the level. The boost on the Ghost does not count as firing a shot. If your Ghost is getting trashed, there is a new one on the other end of the bridge you cross as the Space Elevator collapses. Also, you can climb the hill just after this location using the boost feature, instead of going along the path and getting shot at by the two Shade emplacements.

Play under the Legendary difficulty setting with the Iron Skull on. Two Mongooses you can use as transport will appear inside the first open tunnel you can walk into after starting on the highway. Also accompanying the Mongooses are four rocket launchers with 999 shots. Take each piece of highway slowly and make sure to cover DARE when she gets overwhelmed.

Go to forge. Go to the map sandbox. Spawn a sniper and an energy sword. Pick up the sniper and the energy sword on the ground. Use the sniper and zoom in all the way on the handle. There will be some weird Covenant symbols. If the sniper doesn't work, try zooming in when you're in monitor mode.

Successfully complete the game and do not interrupt the credits. The Epilogue video will begin playing after the credits end.