(Priority) Earth

Priority: Earth

You don't have anywhere else to go but to Earth. Before going there, make your final preparations; upgrade your weapons and mod them as necessary.

The final push

As soon as you land, you don't have time to stand idle; take cover immediately and start tearing the enemy up. Fight your way to the parking lot. Be careful of the brutes and the enemy flankers. Once clear, continue up the building.

Continue to the upper floor and clear the area. Make your way to the shuttle and grab the med-kit and heavy weapons. Grab the Cain, aim it at the cannon, charge and release. Watch it go down in flames.

Once done, dig in and survive the attacking enemies. Wait until your shuttle arrives and throw everything you can to clear your path to the shuttle. Once clear, run towards the shuttle.

You'll be in the forward operations base. You can talk to your current squadmates and even patch to your previous team mates via Communications Tech. Once done, continue surveying the area. As you cross the bridge to the next building, you'll have to man the turrets and defend the perimeter.

Continue along the path and grab the med-kits along the way. Start the attack when you're ready.

Continue following the path and take out the enemies along the way. A harvester will appear eventually so take it out quickly to keep your allied tank alive. Keep clearing your current position until no more enemies appear.

Continue on foot and enter the parking lot. Defeat the husks and brutes. Press on and continue to the upper floor. Take out the enemy forces manning the turrets. Grab the med-kits inside this room as well.

Continue outside and do the same thing. This is pretty much a straightforward path where you need to clear all enemies in order to reach the objective point. In the final stretch, two brutes will attack you in the narrow path. Throw in everything you got then open the door. This will trigger a scene.

After the scene, continue outside. Clear the area then deactivate the firewall controls when prompted to. Dig in and defend the area.

After repelling the initial wave, more enemies will appear from the left flank. Change your positions and take aim. More enemies will appear, including banshees. Once prompted, activate the missile controls. After that, the problems just keep piling up.

The next enemy wave will consists of several brutes. Concentrate your fire one at a time and be careful not to get cornered in a tight position. Keep repelling them until a harvester arrives. When it does, take cover then get rid of the remaining brutes before finally concentrating your fire on it.

The last wave of enemy forces will pour in, including several banshees and marauders. Once you get the prompt to activate the missile controls, run towards it and activate it. Otherwise, the enemies will just keep pouring in.

In the next part, you'll have to rush towards the conduit. After reaching the beam, you'll have to walk to the central chasm and have a conversation with no other than the elusive man.

The Return

Finally you'll meet with the catalyst. You'll have to make one of the three difficult choices. Destroy the reapers, along with all synthetics, control them or sacrifice yourself to make way for a new breed of life through synthesis. Take the path what you think is right then approach it. Watch the ending scenes.

Difficult choices

Crucible docking

Galactic Readiness and Military Strength

Your War Assets count for your overall military strength. These are the notable people, races, armies, ships, etc that you have rounded up for your cause. This will ultimately determine how well you'll do in the last battle against the Reapers on Earth.

However, your Galactic Readiness also affects it – even if Bioware denies that it has something to do with it. You can only increase your readiness by playing in Multiplayer and the IOS Mass Effect game. Unless you do those, your readiness will stay at 50%. This will halve the your total military strength's value. You need to get at least 4000 to 5000 “effective” military strength to get the best ending.

It is easy to get your “total” military strength past 6000 at least. But then again, if your galactice readiness is just at 50%, then your “effective” military strenght will just be around 3000. This is an unfortunate truth for players who prefer to play offline or just don't have access to multiplayer.