I don't remember another puzzle game seducing me that much, except Deadly Rooms of Death, and that's quite the compliment! Thanks a lot, dev team

Anyways, on to the questions :
I remember reading a quest (not sure, but what else could it have been?) popup telling me that doing this or that would unlock a vicious difficulty dungeon. Now I can't find this text anywhere by hovering over the quests still open to me.
But where do I click to actually select a vicious difficulty dungeon?
Or alternatively, did I drink too much and have I actually not unlocked vicious mode?
Here's what I have on my adventure screen :
Halls of Steel : Dancing Blades
Grimm's Grotto : Halfling's Ho
Ick Swamp : Challenge Accepted
Magma Mines : Minecraft
Havendale Bridge : Unlikely Heroes Forest Edition
The Labyrinth : Muu
and Rock Garden : Hard Rock, Unlikely Heroes Desert Edition, Complicated Tasks, pt 4
Hobbler's Hold, Northern Desert, Den of Danger, Western Jungle, Southern Swamp, Venture Cave, Eastern Tundra, Double Doom, Hexx Ruins, The Slime Pit, Creeplight Ruins, Berserker Camp are devoid of quests (I have finished those I had).
The game hasn't proposed me a town upgrade in a very long while, so I suppose no more upgrades are to be had (or maybe when I reach vicious?).
So what am I missing, please?
Secondly, I have unlocked every normal class, plus tinker and transmuter. I have done every normal quest's bronze challenge, yet didn't get the steam achievement 'Hero Literate' - I suppose I must do the special classes bronze challenges - how, they don't have a building to select the challenge from, as far as I am aware?
PS : I am playing the game under Wine/Ubuntu 13, if that might be the cause of my puzzlements, which I very much doubt.