Gallivant around the Galaxy
You will need to win a match on every Skirmish map against at least 1 A.I. If you run down the 1v1 list when in the Skirmish game lobby you will unlock the achievement, 2v2 and 3v3 do not include all maps. Here is the list as follows if you want to copy/paste and check off:
Blood Gulch (1v1)
Chasms (1v1)
Pirth Outskirts (1v1)
Release (1v1)
Tundra (1v1)
Barrens (1v1)
Blood River (1v1)
Beasley's Plateau (2v2)
Crevice (2v2)
The Docks (2v2)
Labyrinth (2v2)
Repository (2v2)
Terminal Morain (2v2)
Memorial Basin (2v2)
Exile (3v3)
Fort Deen (3v3)
Frozen Valley (3v3)
Glacial Ravine (3v3)