Mass Effect has a robust combat system with six classes to choose from. Here is a description of each and a web link to a guide on each one.
1. Adept
The Adept is all about biotics so she can toy around with her enemies in various ways, being able to lift and throw enemies, suck them out of cover, and lower their defense.
The Adept Guide
2. Engineer
This class has all the tech talents, making him the best buffer, but even better is that he can also repair vehicles, improve shields, and heal the party.
The Engineer Guide
3. Soldier
The Soldier is all about the front lines of combat, since he can master all the weapons in the game and is able to withstand the most firepower thanks to his ability to wear heavy armor.
The Soldier Guide
4, Infiltrator
This class can use tech, pistols, and snipers, so he is great for long range combat, as well as being able to disable enemies and then take them out.
The Infiltrator Guide
5. Vanguard
Anyone who likes to throw and lift their enemies around while firing their weapons at them should consider the Vanguard since she can use biotics, pistols, and shotguns.
The Vanguard Guide
6. Sentinel
With a mix of tech and biotics talents, the Sentinel is a rogue, healer, and buffer, a class who can stay back to protect and support his squad during combat; he can heal his party, shut down enemy weapons, paralyze them, suspend them in the air, and lower their defense.
The Sentinel Guide