Full list of all 12 Siegecraft Commander achievements worth 1,000 gamerscore. It takes around 3-4 hours to unlock all of the achievements on Xbox One.
Crash air units into each other
Shoot down an air unit with a keg
Kill a tower with a full power trebuchet shot
Catch a cow with a dragon
Destroy 10 units with a single keg
Destroy a tower with a building projectile
As a tower is being destroyed, fire a projectile and destroy an enemy tower
Get 5 tower kills by destroying the tower it is linked to
Change a cow into a mad cow
Chain 4 Towers with a single Hex Curse
Hit 8 friendly units with the haste spell
Hit 10 enemy units with the freeze spell