Here is the full list of all 12 Star-Twine achievements.
Have 30 Turrets at once
Hit the enemy with 2 missiles at once
Destroy a Sentinel before it activates using one of your own Sentinels
Win a match after getting hit with a Missile
Win a match with a Missile explosion
Finish the single player campaign
Win a skirmish match on Medium difficulty
Win a skirmish match on Hard difficulty
Win a skirmish match on Very Hard difficulty
Win 20 skirmish matches
Win a multiplayer match
Win 20 multiplayer matches