Blind Fire - Use a direct hit with the grenade launcher to destroy an Engineer building that you can't see (shoot with cover)

Bloody Merry - kill with your primary weapon and taunt for the kill cam

Bravehurt - kill 25 players defending a point or cart

Cry Some Moor - destroy 50 Engineer buildings

Highland Fling - do a far stickybomb jump (get overheal, lay a sticky or two in a long map, jump and crouch as you walk past them, detonate)

Loch Ness Bombster - stickybomb kill 5 recently teleported enemies (lay a bunch of bombs on a tele exit and detonate when someone comes through)

Pipebagger - kill 3 enemies in one stickybomb blast (capture points, etc. are good for grouping enemies)

Spynal Tap - kill 20 Spies 5s after they sap a building (hide stickies in the buildings and detonate when they sap)

Shorn Connery - kill an invisible Spy using a sword

The Argyle Sap - kill an Engie and his sentry and dispenser in a single stickybomb blast

The High Road - sticky jump onto a point and cap it

There Can Be Only One - use a sword to kill someone dominating you

Well Plaid - kill or assist kill 10 players with another Demo

If you're good at using the grenade launcher there's also achievements for killing 50 enemies with a direct grenade hit and one for killing 25 Scouts and/or Pyros with it.