1º After canceling canalizations and win the battle, you need to fart on the bodys 5 times and the achievement appears.


2º In the first battle with the gnomes, you must eat mana potions to have all the bar, you need to wait until the second battle with the gnomes, wait until the 2 gnomes on the front canalize at the same time, then drink a speed potion (it give's you 2 turns) and then cancel both canalizations with dragon's farts.


I hope this solutione your problem!