Here is the full list of all 36 Dead Island Riptide trophies - there are 20 bronze, 11 silver, 4 gold and 1 platinum.
Collect all other trophies
Finish all quests in the game
Obtain level 70
Find and kill all the most dangerous monstrosities located in dead zones
Find all the secret files
Find all collectibles
Finish hospital quests for Cecil
Find all pages from the guide book
Find all the volunteer's voice recordings
Finish quests for Dr. Kessler
Kill the Twins
Kill 25 monsters with a chainsaw
Kill 100 monsters using the boat's speed boost
Find 50% of collectibles
Kill 100 enemies using charge attacks
Kill 100 monsters with thrown melee weapons
Rescue 20 NPCs that have been grabbed by monsters
Kill 100 monsters with a kick
Obtain level 50
Complete all the main quests cooperatively with any number of partners
Finish the game
Defeat Harlow
Enter the docks in Quarantine Zone
Make pact with Serpo
Survive the horde on the roof
Gain access to a long-range radio station
Clear out the cinema
Reach Henderson
Kill special enemies: Grenadier, Thug, Wrestler, Infected, Suicider, Screamer, Butcher, Floater.
Successfully defend the tunnel entrance
Install a total of 5 barricades during hub defense
Kill 10 monsters with one mine
Kill 50 monsters by smashing, decapitating or shooting them in the head
Mark 100 opponents which were then killed by your co-op partners
Find a boat for use in the jungle
Escape from the ship