Sentries
Powerful Pipsqueak- Kill 5 enemies with a single level 1 sentry
Brutal Bully- Kill 20 enemies with a single level 3 sentry
"Well, good night, Irene!"- Gain revenge on 20 nemesis using a sentry
Makin' bacon!- Kill 5 enemies within 30 seconds using only sentries
More than just a builder- Kill 3 enemies in 30 seconds using only the shotgun and pistol
DispensersMechanical Medic- Heal 2000 health in one life
We don't need no medics- Heal a total of 150,000 health
Ich bin ein Engineer- Heal 25 teammates to full health without a medic's intervention after they've called for a medic
TeleportersEngineer, B.Sc.- Teleport 20 teammates in one life
Engineer, M.Sc- Teleport 30 teammates in one life
Engineer, Ph.D- Teleport 50 teammates in one life
Teleporter Titan- Teleport a total of 3000 teammates
Please hold, service will be resumed shortly- Rebuild your teleporter entrance 60 seconds after a spy saps it
Spy related
Yellow Gutless Cowards- Wrench 100 spies to death
A bum full of buckshot- Shotgun a spy to death a second after your sentry has been been destroyed with a sapper
Caught in the act- Wrench 5 spies attempting to sap your sentry, and destroy the sapper before it destorys the sentry
Dance Master- Kill a spy and perform the shotgun taunt over his ragdoll
That ain't for you pal- Kill a spy whilst he's healing from your dispensor
Wrench > sapper- Destroy a total of 2000 sappers
KillingHow's that for you dummy?- Wrench to death 50 heavies
Take it like a man, shorty- Kill 200 scouts
Pistol Whipped- Kill 50 engineers with your pistol
Job Well Done- Defend 200 points or flags
Engineer giveth, engineer taketh- Destroy 50 enemy buildings
Friends
Anything for a pal- Teleport 10 of your Steam friends
Miscellaneous
The BlitzBuilder- Build all 4 constructables before setup times ends
Metal Master- Construct a total of 10,000 buildings
Do less harm- Play a full round as engineer and come top in a team of six or more building only telepoorts, dispensers and level 1 sentries
Methinks I've thought about this far too much!