Drakeward Scissorhands



In the room at the very beginning, check behind the divider. There will be an item near a corpse. Pick this up to get a pair of Scissors and the achievement that comes with it. The pair of scissors is actually for a corpse nearby. You need it in order to progress the story.

Guild Master



One of the major objectives in order to progress the game will be to form a guild. In order to do this you have to talk to the Princess' Assistant. You will be tasked with collecting 500 gold, a chicken (from a sidequest), and gathering a group of 6 to become an official guild. Your 6 will be Drake, Candy, Deacon, Sweet Violence, Norai, and Angelina. Once you gather them, talk to the assistant again to formally become a guild master.

Titan Killer



Another major objective in GT2 is to kill the 4 titans. 3 of them need to be defeated before you an access the fourth one. The first titan is the Spider Titan, you can find it while searching for Holy Avatar. The second is Jabba Blob and he will be encountered along the mercenary questline. The third titan is called The Fog and he is the main boss before you discover the that the titans are keeping you trapped in that dungeon. The final titan is called Killer Titan and he is located beyond the second demongate in the Basement.

Animal Activist



In the very first area of the game, talk to an NPC named Prof Oke. She will tell you about pokedudes. As the conversation continues you will have the chance to talk about animal cruelty (making babies fight). Select this option to trigger the achievement.

Goblin Friend



After you meet Riemel, talk to him again for an optional quest. He will ask you to find some goblin brew situated at an altar near a demon gate. Take this back to him for the achievement. The quest reward will be a weapon of your choice (one for Drake or one for a party member).

Mr. Attentive



In the same map where you meet Riemel, you will find Deacon. He will be guarding a treasure chest that he is trying to loot but cannot open. An optional quest will pop up requiring you to look for something to bust the chest open with. If you check the corpses that you previously passed by, there will be a Pickaxe. Give this to Deacon to finish the optional quest. He will reward you with a bloodstone (BUT THAT'S NOT THE END OF IT). Ask Deacon 'Was that it?' in order to get the achievement. He will then reward you with half the gold that was in the trunk.

Slick Talker



After Tevez flees from the spiders, you will have the option of persuading the mercenaries to fight for you. In order for them to assist you, you need to tell them that Tevez is a coward. Any other option will result in failing the quest and missing the achievement so it would be wise to save at least right after you get Deacon.

For the Hoard



There is an optional quest given by Synthia wherein she wants to get a Bodyguard (after you steal a chicken from her). Once you get her that bodyguard, she will reward you. Call her stingy in order to get the achievement.

Holy Avatar / Felja / Rukel



This is a progression achievement. I listed it under missable because it is possible to not get 2 of the 3 achievements on your first playthrough. This is because near the end of the game, you have to choose 1 of the 3 champions from each guild to fight at your side. You will get the corresponding achievement based on who you pick. In order to get them all, simply save right before talking to Zara (after defeating the Fog).

Tough Man



Angelina will give you a set of trials to prove that you are a tough man. The details on this are very vague but I am certain that you at least should NOT lie to the potion seller (the one who falls asleep a lot) and stand up for Angelina when she gets into a fight with Sweet Violence (in the Elven outpost mission). If anyone has further information regarding this then please contribute.

Treasure Hunter



In the elven area of Sanctuary, inspect the tree shown on the screenshot to find a hole that you can reach through. This is one of that trees that you can hug for a sidequest. Here you will find the elven jewelry required for the achievement.