OTHER SIDEQUESTS:
*DISCLAIMER*
Keep in mind that when doing the Feros sidequests, do not kill the colonists. You cannot report back to them if they are dead, or if there are not enough colonists left.
Feros: Varren Meat When you are doing the assignment Feros: Power Cells you will complete this one at the same time. When you kill the Varren that are down in the tunnels you just have to report back to Davin Reynolds and he will reward . Feros: Data Recovery
Go up some stairs in the ExoGeni building, and you will find in a room with 2 or 3 krogans that have no other purpose than to house his console.
Feros: Power Cells You need to travel down into the Tunnels which are accessible by some stairs near the elevator which takes you down to the Skyway. Once down in the tunnels you will need to fight your way through a lot of Geth. You need to go through another set of doors which is about halfway down the path that you are on. When you enter the doors it will do a short cut-scene showing some Varren who seem ready to devour you. Kill all the Varren then move up to the vehicle and look at the front. You should be able to recover the Power Cells that are there. When you have taken the power cells back to Mary O'Connell she will reward you with some coin that Fai Dan left to her. Feros: Water Restoration To complete this assignment you need to travel down into the tunnels and fight your way through the Geth. When you are in the tunnels you need to find three (3) water valves that are located at small intervals along the walkway. You can't miss them because they are nearly the only white objects that are down there. When you have opened all three (3) valves return to Macha Doyle for your reward. Feros: Geth In Tunnels You need to travel down into the Tunnels which are accessible by some stairs near the elevator which takes you down to the Skyway. Once down in the tunnels you will need to fight your way through a lot of Geth. Open up your map to find the location of the transmitter. When you have found the transmitter simply destroy it and you have completed the assignment. Person Of Interest/Hostile Takeover
Hack one of the computers in the C-Sec Academy to pick this one up, after you've completed the first four missions and returned to the Citadel. C-Sec is investigating a suspected criminal named Helena Blake. She's somewhere in the Financial District.
You'll find Ms. Blake outside of the merchant area in the Financial District. She has a business proposition for you: take out two of her crime boss associates, and she'll reward you kindly. You can tell her "I won't do this", if you like, and you'll still receive the coordinates of the crime bosses, in addition to paragon points. When you leave the Citadel again, you can start tracking your targets.
One of them is located in the Dis System of the Hades Gamma cluster, on the planet Klensal. The other is located on Mavigon in the Han system of the Gemini Sigma cluster. When both of them are dead, head to the Fortuna system in the Horse Head Nebula and land on Amaranthine.
You'll run into Helena when you enter the base. You can attempt to talk her into walking away from the gang entirely, if you want some paragon points, but the better solution is to attempt to arrest her, or to simply goad her into a fight. Killing her and the rest of her gang will net you plenty of experience and cash, far more than simply accepting her offer of walking away will.
Geth Activities
You'll find this quest by hacking into a Geth terminal in the upper level of the ExoGeni building on Feros. It details a mass of Geth ships in the Armstrong Nebula; sounds like you should check it out. If you do, Admiral Hackett will fill you on in the locations of four Geth bases. It'll be up to you to take them out.
The outposts are on Gagarin: Rayingri, Tereshkova: Antibaar, Hong: Casbin, and Vamshi: Maji. After attacking the pure outposts, keep in mind that Geth Dropships will usually deposit more forces on the ground. You can shoot down the Dropships with your cannon, if you wish, but it will take a while to do so, and you'll be exposed to fire from the ground troops. Also keep in mind that taking down your enemies on foot will net you more experience than killing them with the Mako; if you manage to wear down a Colossus or something strong like that, you can pop out of the vehicle and finish it off with your weapons for more experience.
When you've destroyed all four bases, the Grissom system will open up, which is where the primary Geth base is located. Land on Solcrum, a small moon of one of the planets there, to find it. Kill everyone in the base and hack the terminals to unlock the Tali and the Geth quest.
Tali And The Geth
On the Solcrum moon in the Grissom system, as a part of the Geth Activities quest, you'll find a terminal you can hack to start this quest. Bring the data back to Tali, and she'll ask for a copy of it for her Pilgrimage. You can withhold it, if you like, or give it to her; it's up to you.
Investigate Samples/Colony Of The Dead
Another quest from Feros; hack the Server Node there to retrieve it. Something about samples that were sent to the Matano system. Head there (it's in the Maroon Sea cluster) and land on Chasca. There are a few settlements here, but everyone around has been turned into Husks. Check the buildings here for clues. In the southwestern facility on the hill (the science station), you'll find a terminal where you can download the logs of the base and complete the mission.
Wrex: Family Armor
If you speak with Wrex in between every mission, he'll eventually give you this quest, which involves tracking down a turian who stole his family armor and is now hiding at a base somewhere in the Argus Rho cluster. Head there and proceed to the Phoenix system and land on Tuntau. Don't forget to bring Wrex along in your landing party.
On your map should be a "hidden structure". Head there and pop inside for a peek. Tonn Actus will be inside, along with a horde of pirates. Kill everyone and poke around in the numerous crates in the back rooms to find the Warlord armor. It's decent enough, but you can probably find better. Regardless, it's what Wrex wanted. Wait until he acknowledges the mission completion, then reduce it to omni-gel to have a laugh at his expense.
Garrus: Find Dr. Saleon
If you speak to Garrus enough during the intermissions, you'll eventually be able to unlock this quest. Garrus was at one point tracking Dr. Saleon on the Citadel, but the criminal managed to escape before he could be brought to justice. He's escaped to the Herschel system in the Kepler Verge. Head there and board his ship, the MSV Fedele, but be sure to bring Garrus along for the ride.
Kill your way through the test subjects in the ship until you find Dr. Heart. He'll claim to know nothing about your Dr. Saleon. No matter how you pursue the conversation, he'll attack you. Kill him and get back to the ship.
ROMANCE SUBPLOTS:
These are easy. All you have to do is speak to Liara, Kaiden, and/or Ashley, depending on who you want to romance. If you're a female Shepard, you can romance Liara or Kaiden. If you're a male, it's Ashley or Liara.
Unlike in KOTOR, these romance subplots are really hard to mess up. You could be a jerk to Liara or Ash, and it won't make any difference, as long as you speak to them after EACH mission. They will enter your room for some lovin' just before you take off to the planet Ilos.
DEPENDING ON WHO YOU ARE ROMANCING, MAKE SURE YOU DO NOT LET YOUR POTENTIALLY ROMANCED ASHLEY OR KAIDEN DIE IN THE STORYLINE. Otherwise you'll be stuck with Liara.
COMPLETE THE GAME ON HARDCORE/INSANE
You are able to reuse your character that you create on your first playthrough. Chances are you aren't going to get to levels 50 and 60 for the achievements on your first try. If you change the difficulty setting
BEFORE you kill ANYTHING at all, it is said that you will still get the achievement at the end for completing it on these difficulties. If you change it in the middle of the game though, you won't get it.
SCHOLAR ACHIEVEMENT - FIND ALL PRIMARY ALIEN: COUNCIL RACES, EXTINCT RACES, AND NON-COUNCIL RACES CODEX ENTRIES Aliens: Council Races Asari
Speak to Asari Consort
Salarians
Speak with Captain Anderson about the Council
Turians
Speak with Nihlus in the com room before Eden Prime
Aliens: Non-Council Races Batarians
After you become a spectre, ask Anderson about his past mission.
Elcor
Go to the Embassies, Volus and Elcor Office, talk to the Elcor.
Volus
Go to the Embassies, Volus and Elcor Office, talk to the Volus.
Geth
After Eden Prime, ask Anderson during the debriefing.
Hanar
Speak to the Hanar shopkeeper in the Financial District.
Krogan
Complete the quest to get Wrex in your party.
Quarians
Complete the quest to get Tali in your party.
Keepers
Speak to the Avina Terminal ouside the Citadel Tower and ask about the Keepers.
Aliens: Extinct Races Rachni
Speak to the Avina Terminal in the Financial District and ask about the Rachni War
Prothean
Speak with Nihlus in the com room before Eden Prime.
There are plenty of ways to get most of these entries, but this is how I ended up doing it.