I'm pretty sure that Gnome 3 is unbeatable. Judging from the dev's reactions to the previous solutions of just focusing on one monster and then taking on the boss, I'm certain that I'm supposed to kill all monsters, level up to level 3 and then take on the boss. But, I come up 2 exp short.
EDIT: My post was approved finally. I thought it was rejected. So Slow adds +1 EXP on kill? There's still no way you can finish two enemies off with WETWUT and still have enough left over to kill the third enemy though.