Here is the full list of all 27 Skulls of the Shogun achievements.
Earn 30 gold skulls.
Complete every level such that your best times for all of them add up to less than 4 hours on Normal difficulty.
Complete the Forbidden Islands on Normal difficulty.
Complete the Forbidden Islands with 10 units or more.
Bring back a fallen unit with a Demon Fox Monk's Revive spell.
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.
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.
Acquire 100 emblems.
Have an emblem upgraded to Gold status.
Defeat a General with a Tanuki taunt.
Acquire your first "Very Rare" emblem.
Complete the Land of Frozen Fortunes on Normal difficulty.
Earn 15 gold skulls.
Complete the Shores of the Dead on Normal difficulty.
Complete the Land of Eternal Blossoms on Normal difficulty.
Complete the Land of Monsoon Meadows on Normal difficulty.
Complete the Land of Golden Harvest on Normal difficulty.
Power up your General to a Demon.
Defeat an enemy Monk by haunting its Shrine.
Earn 60 gold skulls.
Earn all 72 of the Bone-A-Fide Edition Gold Skulls.