Here is the full list of all 50 Overfall achievements.
Kill all 6 troll types.
Meet the Dwarf Tradelord as an ally.
Unlock all classes.
Beat the game without using Dust's speed boost.
Meet the Goblin Freeman as an ally.
Beat the game without buying food from bazaars, inns or trade-boats.
Meet the Forsaken Redeemer as an ally.
Recruit Pyromancer and Ice Maiden to the same party.
Beat the game.
Meet Ezel.
Kill the Vorn King.
Meet the Elf Queen as an ally.
Upgrade a utility skill.
Upgrade a weapon part.
Collect 1000 runes.
Spend 4000 foods.
Bank 100 dusts in a single playthrough.
Win 1000 battles.
Kill 700 Everguards.
Kill 500 Undeads.
Kill 20 Jarls.
Kill the Vorn King 10 times.
Take 1000 quests.
Become Exalted with all races.
Unlock all class trinkets.
Unlock all neutral trinkets.
Unlock all weapons.
Unlock all utility skills.
Unlock all companions.
Unlock everything.
Beat the game with every class.
Visit every single island on the map.
Visit every single inn on the map.
Acquire every persona in the game.
Play with every possible hero combination.
Kill the Everking with your last surviving party member.
Win a battle with the last surviving party member and 1 HP.
Recruit 10 companions in a single playthrough.
Resurrect an ally at Altar 7 times in a single playthrough.
Hit a critical strike while applied with Blind and Chilled.
Beat the game without upgrading your utility or weapon skills.
Meet the Orc Warchief as an ally.
Meet the Hollow Alpha as an ally.
Kill the Vorn King with Hidden buff on you.
Die with Retaliation or Bone Pore's damage.
Reach the Citadel without a companion.
Beat the game without using a mobility skill.
Kill all enemy classes. (except Vorn King and Everking)
Destroy the first 3 Vorn ships that just came out from the portal.
Maintain a party with 3 greathammer wielders.