> Can anyone give me some pointers as to how to face King Brewelry on Level 5?

Brewlry is tough. Fortunately, you'll be happy to note that while the extra stuff you could have gotten on the prior level would have helped, the battle is still quite doable without it.

First, play very cautiously. As you know, there's a portal right nearby, so you don't really lose anything by running away. When you get even close to low on hit points, instead of healing yourself in battle, run away. Head back to the portal.

The other thing is, be smart about what items you plunder from the nearby cache. There are certain items there that will be extraordinarily helpful to you. If you don't want to risk death and a big setback by experimenting with items on Brewlry himself, backtrack and find some freeborns to try things out on. There are a couple different ways to approach Brewlry, but one or two of the items are particularly devastating.

I assume you know there's another whole area you can get to to clear out -- the one next to the plinko board. Maybe that was the progress you lost when you died? Normally, in the face of a difficult battle, I'd recommend avoiding it until last, when you have become more powerful from beating the rest of the level, but in this case I'd say to go straight for Brewlry (behind whom there are checkpoints), and then you can work on clearing that other room with the four reds and a few blues when you can do so without risking losing so much progress.

Again, the keys are taking the battle in stages, running away frequently to recoup, and judicious item selection.