Here is the full list of all 12 Iron Sea Defenders trophies - there are 7 bronze, 4 silver and 1 gold.
Build 50 towers
Kill 1000 enemies
Kill 500 enemies with the secret weapon
Sell 50 towers
Launch 100 waves on one map manually
Get 100 000 coins
Complete level when your castle has 1 HP
Build 1000 towers
Kill 50 000 enemies
Fully upgrade 200 towers
Sell 500 towers
Complete all levels with 3 stars