Original title: Winning Entries of 2025 - The 29th IOCCC
Article
The IOCCC29 announcement details where to access the 2025 winning entries, including indexed pages, source code, author remarks, and a downloadable archive. Judges described submission volume and quality as unusually high despite the contest’s second consecutive run after a long hiatus, attributing results to cleaner workflows, stronger web presence, and stronger derivative work from prior winners. The post-contest process was documented more tightly, with YouTube segments for each winner, clearer updates to entry pages, and better submission and judging procedures. New fun challenges were added to entry pages with a GitHub workflow for contributors to improve solutions or submit alternatives when challenges remain open. The contest rules and guidelines were substantially rewritten for 2025 (rules 29.15 and guidelines 29.08), and judges said they may continue refining IOCCC30 operations through 2026 while preserving the same approach to contest documentation. The entry highlights include several notable winners across emulator, obfuscation, gaming, and data-generation themes, with multiple entrants from prior winners and a first-time geographic expansion. Non-winning participants are encouraged to iterate and resubmit, and the organizers acknowledge that several 2025 winners were improved forms of earlier non-winning work.
Community reactions celebrated specific entries, praising the Game Boy emulator and the 366-byte OISC VM that can run Linux and Doom, while also noting cultural references such as Frieren in the Zoltraak-themed submission. Several commenters highlighted that the IOCCC allows LLM use in its rules, and some argued the website’s obfuscated structure can make finding source files difficult. There is mixed sentiment about the contest’s direction: one group values the winners and craftsmanship, while another says the submission process feels confusing and that modern software contest formats may be less compelling. Some participants expressed nostalgia for Underhanded C, citing it as more engaging and lamented its inactivity. Others questioned whether LLM-generated obfuscation undermines the contest’s meaning, pointing out that models can intentionally produce obscure yet correct C from readable code. A final comparison likened IOCCC’s award structure to a film festival with many prizes and no single top prize, framing the format as both playful and structurally unusual.