I managed to beat the level with Mines, Molotovs and AK-47, but it took me about 25 tries to do so. (Now I have a red face, haha, you're not alone here) I hate using the sawn-off shotgun, but most players say that this is the way to go on this level @Bakkart.
@yolomas18 are you sure you defeated challenge and decayed mode? they have stars too as noted above
Now, if that's your shame @bakkart, it may make you feel better knowing I can't get past level 7 (the one with the Lobber hordes). Mines, machete and AK so far. Haven't unlocked much better stuff anyway.
*EDIT* Gotten through that but barely.. Less than half health remaining in the end and the final undead blocking my shots at the 2 remaining Lobbers...
I don't know about you, but I can't get the "Weapon of Choice!" quest. I mean, I bought all the weapons and upgraded all of them to the max level, but I still don't get the quest
edit: wow! I was ninja'd