Complete levels 1 to 4
Complete levels 5 to 8
Complete levels 9 to 12
Complete levels 13 to 16
Complete levels 17 to 20
Complete levels 21 to 24
Complete levels 25 to 28
Complete levels 29 to 32
Complete levels 33 to 36
Complete levels 37 to 40
Complete levels 41 to 44
Complete levels 45 to 48 and finish the game
Sink a Sub
Sink a Frigate
Sink a Destroyer
Sink a Battle ship
Use every item at least once in a single session
Complete a level without using any special weapons
Sink a Carrier
Sink a Cruiser