Try one gun
A single weapon build makes for insanely fast power recharges. With one gun, ammo is a concern, make sure youre hitting the ammo crate early and often and try a Spare Thermal Clip mod. A versatile and high capacity assault rifle is often your best bet, but a Krogan Soldier with just a shotgun can unleash a ton of Carnage. Its fun with a Vanguard too. Also, the Engineer works fine as a single weapon class, youll be pumping out Incinerate and Overload so fast you may forget to fire. Try them with a Sniper Rifle!
Stasis is the Asari's best asset
Both the Asari Adept and Vanguard get Stasis, a biotic Power that gives enemies a case of lockjaw for their whole bodies. Its phenomenal against quick moving enemies, like Cerberus Phantoms. Freezing enemies in place for your teammates makes you an assist monster. You can hang back and set up easy kills for a sniper, or go in close and freeze targets for a Krogan to crush. Stasis is also a great opener for biotic combos, choosing Bonus Power at Rank 5 gives you a chance to follow up with Warp or Biotic Charge with no cooldown. Choosing Bubble at Rank 6 makes Stasis into a crowd control power that rivals the Adepts Singularity.
Salarians and sniper rifles
The long range power of a sniper rifle makes a great follow up after a Salarian Energy Drain. Best of all, the Salarian Operative power can boost headshot damage and reduce the weight of sniper rifles. Try a sniper rifle as your only weapon for super fast power cooldowns.
Energy Drain is a Geth's worst nightmare
When youre facing Geth, you want a Salarian Engineer or Infiltrator on your side. Their Energy Drain lets them feed off Geth like vampires. It sucks their shields dry and stuns weaker troops. For the ultimate in anti-synthetic combat, choose Drain and Armor Boost for Rank 5 and 6 of Energy Drain.
Infiltrators and Engineers are great for objectives and rescues
Going invisible with Tactical Cloak makes the Infiltrator the perfect class for swooping in to capture objectives and revive teammates, especially with Rank 4 Duration. The Engineer is good for this too; Drone, Turret, or Decoy can provide cover and buy you time.
Tactical Cloak + shotgun or sniper rifle = Win
Infiltrators get a major damage bonus right after they come out of cloak. Use it to make the most of the deadly blast from a shotgun or sniper rifle.
Build a heavy weapons Soldier
Soldiers arent the kind of class that wait around for power cooldowns. They shoot, shoot, and shoot some more. So give em the big guns, who cares about cooldown times? The occasional Concussive Shot or Frag Grenade is just icing on the cake. For a mid-range badass, equip a Soldier with the heaviest shotgun and assault rifle you have. For long range power, swap in a sniper rifle, Marksman will make you a real dead eye.
Biotic basics
Biotic attacks are great for wearing down armor and tearing apart weaker enemies. Moves like Warp and Throw home in on targets slightly; you can hook your shots and flout enemies behind cover by aiming up slightly. This is also important whenever youre using cover, so your attack clears whatever youre hiding behind.
Biotic combos
Biotic combos are how you really unleash hell as a biotic. The first move charges the target, the second detonates him, and maybe some of his buddies, too. The Adepts Singularity is a terrific opener, any enemy caught in its field will be primed for detonation. You can follow it up with a Warp, but youre also setting up any biotic on your team for a powerful finisher. As a Sentinel, Throw followed by Warp is a great combo. Shockwave is good for detonations too, and it can be a powerful opener if you choose Lifting Shockwave at Rank 6.
Krogans love the Geth Shotgun
A heavy Claymore is the obvious choice, but if you unlock a Geth Shotgun, youve got to try it with the galaxys best shock troop. Just like a Krogan, the Geth shotgun is slow and powerful but has surprising range. It takes a few seconds to charge up a shot, so you dont want to miss, but a Krogans extra defense will give you the time you need to aim while under fire. Its versatility makes it viable as your sole weapon, boost its capacity with a Spare Thermal Clip.
