Priority: Tuchanka is the final Mass Effect 3 main mission, featured in the first act.
Those who complete Priority: Tuchanka will be able to advance in the game, and start the second act, which means that this mission is not optional.
Our Mass Effect 3 Walkthrough Act 1 – Priority: Tuchanka explains how to complete the final mission of the first act, from beginning to the end, offering tips and tricks on how to defeat the final boss, and where to look for the most important items, while exploring Tuchanka.
Priority: Tuchanka is unlocked after Priority: Surkesk, however, between these two missions, you should complete several side-missions and N7 missions in order to level up your characters.
When you are ready to begin the mission, open the Galaxy Map available on Normandy, select Krogan DMZ and finally Tuchanka. When you enter the orbit go to the Shroud Facility.
Assuming that you have followed our walkthrough up to this point, after you enter the orbit, a dialogue starts and you have to make a very big decision, because Salarian Dalatrass Linron will ask you to sabotage the Genophage.
NOTE: If you accept her offer, (Renegade decision), the Salarian fleet will be added to your collection of War Assets. If you decide to cure the Genophage (Paragon), then the Krogans will support you, but you will receive less help from the Salarian fleet. Additionally, Mordin Solus will die.
We decided to stick with the Krogans.
Select your crew and weapons, and then watch the next cutscene.
Your first objective is to protect Eve from the Husks that attack you in waves. Use a shotgun to dispatch the Husks.
Next, mediate the dialogue between the Krogans and Wreav. Choose your answers wisely, to earn up to 21 Paragon/Renegade Points.
When you reach the first drop-off point, look to the ground and you will find a Med Kit (darker area in the center). Head left and next to one of the Krogan Scouts, is another Med Kit, and the Graal Spike Thrower.
Now, turn back and look near the mobile units for the Shotgun Smart Choke, Death Mask, Pistol Melee Stunner, and Pistol Magazine Upgrade.
After you pick up all these items talk to the Krogan Scout near the edge of the platform.
Objective: Escape the Catacombs
Watch the cutscene and enter the ruins.
Follow the only existing tunnel, which will lead you to a room featuring two exits. The one to the left will take you to a smaller room. On the right wall, above the paintings is an Ancient Krogan Artifact.
Get it, then use the other tunnel to advance. Go around the rocks in the next area (after you reach the lower level), and you will enter another tunnel. Near the entrance check the painting on the right wall for another Ancient Krogan Artifact.
Examine the Ravager Corpse at the bottom of the stairs, in the next area, and then go all the way up to exit the Catacombs.
Your next objective is to move towards the trucks. The path is very clear and you cant get lost in the ruins, as long as you follow the marker.
There are no important items in the next areas, but there are various enemies, including Husks, Cannibals, a Brute and Ravagers. While the Husks are easy enemies, remember that you can take out a Cannibal faster by aiming for its mouth, and that you must avoid the Brutes all the time.
Against the Ravagers, use the Armor Piercing Rounds. Advance slowly, from cover point to cover point until you reach a large bridge guarded by four Krogan Statues.
Jump over the gap and watch the Thresher Maw coming to surface. Continue towards your objective and you will reach a large court guarded by statues. Kill the Marauders, the Cannibals and the Husks that attack you.
The exit point is on the left side, at the end of the area. On top of the stairs (near the statue) you will find the SMG Scope. Follow the stairs down, advance and go up, then right.
Watch the next cutscene and when you exit the vehicle, complete the dialogue and immediately take cover. Secure the area and head towards the Shroud, using the stairs on the left side.
When you reach the top, on the ground, to the left, is the M-5 Phalanx. Take it, then continue to advance until you see the huge Reaper in front of you.
To kill the final boss, you must follow Wreavs instructions and activate the two hammers located on the right side and on the left side of the central plaza.
During the first phase, you have to stay in cover all the time, and you have to reach the other side of the first area. One hit from the Reaper will take you out immediately. Move from one point to another, just like you did when you encountered the auto-turret earlier in the game.
When you reach the other side, you will get help, and the monstrosity will be distracted, however you must kill five Brutes. Stay mobile all the time, and use your preferred strategy against this type of monsters. After you clear the area, activate the first Maw Hammer, but make sure you avoid the legs of the Reaper. Sprint and coordinate your moves. Repeat the same step for the second Maw Reaper and the boss will fall.
Watch the final cutscene showing the death of some characters based on the decisions you made so far in the game. In our case, Mordin Solus died, as well as Eve.
The first act of the game ends with this mission, and the next act starts with Priority: The Citadel.
When you return to Normandy, talk to Hackett and Garrus, then complete the second dream sequence. Remember that your task is to chase the kid in the forest.
Note: At this point, you can start the second act of the game; however, keep in mind that some side-missions, and Citadel missions will be locked if you dont complete them before Act 2.