Engineers don't usually get to spray the room with bullets a la Rambo, but they can win battles in their own sneaky way. This post is just a personal collection of my favourite Engineer moments, taken from ME, ME2 and ME3, on Insanity mode. Updates will be on-going.
Tech powers didn't play as much of a part in my playing style in Mass Effect as they did in the later games. It was satisfying going through mostly with a pistol and (on later playthroughs) a sniper rifle, although Electronics and Damping certainly got used a lot in close quarters. In ME2 especially, however, I went through several missions without firing a single shot. Other missions, containing enemies that tried to flank me, required the occasional single headshot to finish an almost-fallen enemy off. Environmentally-conscious Engineer Shepard doesn't know this "thermal clips littering battlefields" you speak of.
Mass Effect: Geth Colossus on Ilos
Decryption is one of the first abilities I put points into. I switch to another ability once I've reached Master Sabotage level, but it's worth obtaining the final three ranks before the end of the game. This ability's crowning moment came during the aqueduct section of Ilos: Standing still right in front of a Geth Colossus while shooting at it with my trusty HMWP Master Pistol X. Decryption prevents it from using any weapon on you. The cooldown time of Decryption at this rank is just shorter than its duration, so the moment the Colossus starts shaking the effect off, you can activate it again. Combine it with the Master Marksman talent to feel like a Real Soldier, Dammit.
ME2: Lair of the Shadow Broker: The Shadow Broker
This fight involved making use of the Combat Drone, which most enemies consider an irresistible target. With its short cooldown time, a drone can be released every few seconds right next to the Broker, who will always turn to face it, leaving you free to use Overload on his shield. Once the shield is down, Incinerate coupled with shots from the M-6 Carnifex (the weapon I use for almost all of ME2) will bring down the Broker's armor. Anytime the Broker looks towards Shepard, a Drone will draw him away again. Good Drone.