Complete the game on the "Insanity" difficulty level without changing the setting
You need to complete the game on Insanity difficulty setting, this may seem fairly straightforward if you have played through the first game but be prepared. This time around you will be tested. It will require planning and patience.
- Level up your character. Make sure to do the side-missions.
- Make good use of cover and all abilities, if you run around in the open you won’t last long. Make sure to use your armor and shield destroying powers.
- Make sure you also upgrade your weapons and armor
- Balance your team; make sure you have a long range and short-range crewmember with you.
- Know your enemy. Learn the attack patterns and weaknesses of your foes, and exploit them to your advantage.
Miranda is possibly the best squad member to use, as she has both overload and warp to take out barriers and armor, as well as overload to combat shields. Cerberus Operative (passive power) will also boost your squads damage output.
Grunt is another good member to use. He is a damage sponge; packing strong shields and a good amount of health. When you unlock fortification (loyalty power), he gets even better. He also has a good damage output.
Legion has some great synergy with Miranda. When you unlock the researchable sniper rifle for him, he does some great damage. Partnered with Miranda's Cerberus Operative power, he's lethal at long ranges and can rip through armor.
The Sentinel and Soldier are the strongest classes to tackle Insanity.
The sentinel is very durable and versatile. It packs both biotic and tech powers, and can take down armor, shields, and barriers. It's tech armor power is an extremely strong shield boost that lasts until destroyed, which will result in an AoE explosion, damaging everything around you, and it also boosts the damage of your other powers. When you hit the higher ranks, you can take a real beating before it breaks. The Defender passive power provides even more survivability by boosting health and it also gives you other bonuses like damage. Overall, it's a very strong class.
Tip: Reave is a good bonus ability for a sentinel. (unlockable or research advanced training). It's like a super-powered warp. It gives you a health boost and does double damage to armor and shields. Another great option is warp ammo, which can really boost your damage output and help take down those pesky barriers and armored enemies.
The soldier is a pure combat focused class. It possesses a high damage output and good survivability. It also has strong combat abilities to boost it's damage and effectiveness; incendiary ammo helps to take down armor, and disruptor ammo is very effective against shields. Concussive shot knocks down enemies and gives you a little breathing room, and adrenaline rush will cause you to go into slow-mo, allowing you to do some real damage unpressured.
Tip: Warp ammo is devastating on a soldier. With the Revenant LMG, you can tear through armor and barriers with it turned on. Research it if you can with advanced training, or use it if you unlocked it and are starting a new playthrough. Another option is to take a defensive power like shield boost, barrier, or fortification, which will greatly improve your survivability.
Should I just blow through the game without doing side-missions?
No, it is suggested that you do the side-missions and mineral grinding. You don't have to do every single quest or survive the suicide mission for the achievement, but you need to keep your weapons and armor upgraded or the enemies will become too difficult for you to take down as the game progresses.
Should I make a new character or import a high level?
You are better off starting a new character imported from a ME1 save, AFTER completing one playthrough of Mass Effect 2. You will get the best of both worlds; ME1 bonus levels, credits, and resources, and for completing ME2 you will get 200,000 credits, plus 50,000 of each resource and a 25% experience bonus.
Importing a high level character will pit the enemies difficulty curve against you. You won't have as many upgrades, and it will be a struggle. Starting a new character will give you some breathing room at the beginning of the game to pick up some upgrades and level up before the curve kicks into high gear.