Since March I've been working through level design, and I can finally say that all of the game's levels are complete! Once I had all of the cave mechanics and art it was head-down into the content trench, and now I can start working on the final area - the encounter with Grampinald.
Meanwhile, the bugs/tweaks/improvements list grows, but I think the end is actually in sight. Shooting for a release around October or so!