Here is the full list of all 27 Skulls of the Shogun achievements.
Complete the Shores of the Dead on Normal difficulty.
Complete the Land of Eternal Blossoms on Normal difficulty.
Power up your General to a Demon.
Bring back a fallen unit with a Demon Fox Monk's Revive spell.
Earn 15 gold skulls.
Acquire your first "Very Rare" emblem.
Complete the Land of Monsoon Meadows on Normal difficulty.
Complete the Land of Golden Harvest on Normal difficulty.
Complete the Land of Frozen Fortunes on Normal difficulty.
Defeat an enemy Monk by haunting its Shrine.
Defeat 5 foes at once with a Salamander Monk's Lightning Storm spell.
Knock 3 foes off a ledge at once with a Demon Crow Monk's Typhoon spell.
Earn 30 gold skulls.
Earn 60 gold skulls.
Break a Deadly Alliance in online multiplayer.
Win an online multiplayer match.
Win a 4-player online multiplayer match.
Win a team deathmatch game with your teammate still alive.
Win a multiplayer match with a 20-second-per-turn time limit.
Win an online match that lasts at least 30 rounds, defeating at least 30 enemies.
Complete every level such that your best times for all of them add up to less than 4 hours on Normal difficulty.
Acquire 100 emblems.
Have an emblem upgraded to Gold status.
Complete the Forbidden Islands on Normal difficulty.
Complete the Forbidden Islands with 10 units or more.
Defeat a General with a Tanuki taunt.
Earn all 72 of the Bone-A-Fide Edition Gold Skulls.