So, my roomie and I actually played through this last night. We had a few 3rd level characters sitting around for my 4e campaign I'll be starting in a few weeks, so he grabbed three of them and I ran him through it. He had a dwarven cleric, a half-orc barbarian, and an eladrin swordmage.
I got a couple WTF? looks at some of the creatures and a few "this is surreal" comments. He made the saves for the enveloper weakness every time unfortunately, so they didn't get to make any attacks and pretty much just died without doing any damage. The kercpa's kicked butt though, did a crazy amount of damage. Ranged minion FTW.
I wasn't sure what exactly what would threaten the carbuncles, so I ruled that if the players murdered anything within 3 squares of a carbuncle, it would attack. He got a kick of their attack and die schtick.
The second encounter was even more brutal. The brain mole didn't succeed at dominating anything, but he focused fire on the Kow and the Stale Trail Flail Snail (that after the Snail Fail unleashed several rounds of the Snail Wail). The rabbits were actually fairly dangerous with their hit and run attacks and were the last things to die. He blew all his daillies, APs, and a couple healing pots to get through this one.
The last encounter was actually pretty easy, though really annoying. It took forever for him to trudge across to the tower, with the flumphs floating over the water out of reach and launching hit-and-run attacks, while the Gnome hurled mushrooms at him that slowed his advance dramatically.
The round Francis first died, he said, "Badger badger badger... I just noticed there's a badger and mushrooms." Prophetic, since at the end of that turn, I said, "you hear backbeat and the flumphs chant "Badger badger badger badger"".
All in all it was pretty entertaining, though the last fight was a slow painful slog. It was perhaps more fun to read than to play, since it was tough enough that the joke of it was somewhat lost...