Half-Life 2 achievements

Save all buildings outside the missile silo from destruction.

Squish every antlion grub in Episode Two.

Kill a Combine soldier with his own grenade.

Find and break every web cache in Episode Two.

Defeat the chopper in Episode Two without any misses.

Send the garden gnome into space.

Kill a Hunter with its own flechettes.

Kill five enemies with the same energy ball.

Use flares to light 15 zombies on fire.

Finish the game firing exactly one bullet. Grenade, crowbar, rocket, and Gravity Gun kills are okay!

Kill 30 enemies with thrown physics objects.

Run over 20 enemies with the car in Episode Two.