This dungeon crawler is built inside a 200,000 page PDF

A redheaded woman stands in a courtyard
(Image credit: Lucas Cimon.)

Undying Dusk might have a credible claim at being the longest choose-your-own-adventure book ever written, cramming a fully-featured dungeon crawler into a hefty 200,000 page PDF file.

Available for free over on, Lucas Cimon's retro RPG doesn't immediately jump off the page—after all, there are dozens of classic dungeon crawlers on the store. That is, until you realise the game is effectively one giant book, each page a single frame of its sprawling labyrinth.

It works in the same way as any old paperback adventure book. But instead of explicitly saying "turn to page 56 to slay a goblin", each page has a faux-UI full of directions, actions, and menu buttons that link to other parts of the document. There are even musical cues, with soundtrack buttons that'll open your web browser to play some fantasy tunes.

Cimon claims that, to the best of his knowledge, this is "the very first video game in a PDF format". That might not be entirely true (a cursory search shows some simple noughts-and-crosses games and a now-broken maze), but Undying Dusk is certainly the most elaborate—a fully realised fantasy world featuring 10 locations, an overworld, and a cutscene-driven plot. In keeping with the spirit of old adventure games, it's also pretty brutal, sporting thousands of game over screens and only a single path to victory.

Undying Dusk is free to download. Cimon recommends playing it on Sumatra, though it should be playable on pretty much any PDF reading software (except Adobe Reader, for technical reasons).

Natalie Clayton
Features Producer

20 years ago, Nat played Jet Set Radio Future for the first time, and she's not stopped thinking about games since. Joining PC Gamer in 2020, she comes from three years of freelance reporting at Rock Paper Shotgun, Waypoint, VG247 and more. Embedded in the European indie scene and a part-time game developer herself, Nat is always looking for a new curiosity to scream about—whether it's the next best indie darling, or simply someone modding a Scotmid into Black Mesa. She also unofficially appears in Apex Legends under the pseudonym Horizon.