I can use nearly everything in Vornheim at the table in the rainy city.
- The Immortal Zoo of Ping Feng: I have some scattered notes for adding a zoo to the rainy city. Ping Feng's zoo is better. Also, it is ready to run, rather than being just some scattered notes. I can drop a "living" version of it straight into my game.
- The Library of Zorlac: Again, this place will fit right into my town with no changes. It is interesting, atmospheric, and eminently gameable. Also, the random books table on page 49 is the kind of table I should have made a long time ago considering how many books have been looted in our campaign. And the rules for libraries on p. 41, as well. Zak, thank you for these. Combined with Chris Pound's Dying Earth Spell Generator, I'm much better prepared for dealing with books both arcane and mundane in an interesting fashion.
- The floorplan shortcut: Ingenious. I often need floorplans for break-ins. For more complex manses, I have printouts of floor plans from here. For simpler domiciles of the well-to-do, I have relied heavily on Georgian townhouse layouts. Both require having things printed up and ready to use, which I usually can manage. But this little shortcut will add variety and simplicity when I need floorplans in the moment. It is one of many clever, useful shortcuts in the book that I'll be able to use directly. There's a lot of ingenuity on display in Vornheim's approach to on-the-fly city generation and play, and the floorplan shortcut is just one of many examples.
- The tables: Everyone loves these. I do too. I'll be filling the ranks of Embassy Row from the aristocrats table. And then there are the tables for city NPCs, for shopkeepers, for contacts, for connections between NPCs, for encounters, for searching the body, and for magic effects. All useful, all atmospheric, and all with gameability.
This is a damned good game book. Even the first part of the book, which presents Vornheim itself, is full of material that can be directly incorporated into any city campaign. The whole book lives up to the subtitle ("The Complete City Kit"), not just the ingenious shortcuts and excellent tables.
I haven't actually used very much published OSR stuff at the game table directly. Our rainy city adventures have been played using either the D&D Rules Cyclopedia or The Fantasy Trip, so I haven't needed retro-clones. Other than my rulebook and my own notes and printouts, the only other stuff I've actually used so far in the campaign are Jason Alexander's Halls of the Mad Mage and Jeff Rients's Miscellaneum of Cinder. Vornheim goes straight into the gaming bag for future rainy city sessions.