The Only way to play Sentinel on Insanity (and any difficulty)!!!!
##I am Sentinel, and you can too!
Class Skill: Guardian
Skills that you will utilize:
Reave Tech Armor Overload
Garrus/Jack Anyone else
Everything Biotic Everything Tech Everything Assault Rifle
The first step is to get Reave as your bonus skill, this is going to be your most important skill, with Tech Armor a close second, Reave allows you to disable most barriers and armor, and be able to kill most organics in one shot when fully advanced. Advance Reave to heavy Reave after Tech Armor is advanced to Power Armor.
Tech Armor is the skill that really makes the Sentinel possible, like fortification/barrier/geth shield except the fact that it never wears, this allows you to be able to throw up another Tech Armor as soon as the first one drops down. Giving you time to hit the enemy with Reave, shoot them dead or retreat to cover. Advance this first and advance this to Power Armor.
The third important skill is Overload this allows you to strip any enemy of their shields. Especially when upgraded to Heavy Overload with all the upgrades the damage increases tremendously and the cooldown minimal.
Your main focus when going into to battle is to observe the field for anyone with a shield or barrier, if Shield Heavy Overload, if barrier or armor Reave. Have your sqaudmates intercept anyone who tries to flank you, you don’t want that, especially on Insanity even if you throw up another tech armor you only have a few seconds to save yourself.
At the beginning of the game one of your first priorities is recruiting Jack and getting her loyalty mission. Its gonna be awhile until you can get Garrus’ Armor Piercing Ammo and this is the next best thing Warp Ammo, it attacks enemies on every defense they have, combined with the power of an Assault Rifle and its deadly, even on Insanity. On Normal/Veteran I could take out a Harbinger with about 5 secs of fire and one Reave. And make sure you get Garrus’ squad AP ammo ASAP, Sqaud AP ammo does more damage then Heavy warp ammo. Your best bet for another squad member will always be Grunt because he can takes hits, deal damage and be used to protect you when you can’t protect yourself.
At the beginning of the game you’ll be very limited in your arsenal, that’s why its important to get through main missions quickly so you can get hold of the Assault Rifle specialization. Take care to do the Tali Recruitment mission on Hardcore/Insanity to get the Geth Pulse Rifle, it’s the best one you’ll have access to, and yes that’s including the Collector’s Assault Rifle. It’ll probably the only weapon you use ever again.
Hopefully with this guide you'll fall just as in love with Sentinel as I did. (I know you will.) Good luck out there Commanders.