Here is the full list of all 35 Dead Island Riptide achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Finish the game
Enter the docks in Quarantine Zone
Make pact with Serpo
Finish all quests in the game
Find and kill all named champion monsters located in dead zones
Find all collectibles
Find all voice recordings of a journalist
Find all pages from the guide book
Survive the horde on the roof
Gain access to a long range radio station
Finish quests for Cecil in hospital
Finish quests for Dr Kessler
Reach Henderson
Kill special enemies: Grenadier, Thug, Wrestler, Infected, Suicider, Screamer, Butcher, Floater.
Successfuly defend the tunnels entrance
Kill 100 enemies using charge attacks
Kill 100 zombies using boat speed boost
Kill 100 zombies with thrown melee weapons
Find a boat to travel through the jungle
Find all the secret files of Consortium
Kill 25 zombies with a chainsaw
Kill 10 zombies with one mine
Complete all the main quests cooperatively with any number of partners
Deafeat Harlow
Gain level 70
Rescue 20 NPCs from clench
Kill the Twins
Find 50% of collectibles
Clear out the cinema
Mark 100 opponents which then were killed by your coop partners
Install 5 barricades in any hub
Kill 100 zombies with a kick.
Kill 50 zombies by smashing, decapitating or shooting them in the head
Escape from the ship
Gain level 50