Get the killing blow on a Rat Ogre.

Complete the Horn of Magnus

Equip a Trinket for the first time.

Collect your first hidden Sly mask.

Find a soldier with the Gift.

Successfully assault an Overseer UFO.

Kill an alien while flying. Single player only.

Build a Laboratory.

Get satellite coverage over every country on one continent.

You convinced Zeke Sanders to let his hostage go.

You made it through an entire hostile area without so much as a squeak.

Kill an oryx. (campaign only)