Last night I added a new item (instant coffee!) and a new monster (zombie scientist!) and coded what is basically a joke involving the two of them. Writing the joke wasn't entirely a waste of time, as it will actually be useful for other game situations.
I also shrunk the size of the prologue level in the hopes that it'll be interesting. A couple of bugs were squashed. One minor (a display glitch when a thrown item hit a wall) and the other more serious -- an infinite loop that occasionally happens in the tower generator code. I'd never seen it before because it seemed to happen only when generating really small towers, and about 1 times in 20. Of course, it might have been possible for it to happen in the larger levels, but was perhaps very rare.
Tonight I will work on having handedness in the game, in the sense of the player being able to wield something in each hand and the various consequences of that.