Rinsma explained that it’s already “relatively well-known” that PDFs can support a number of features such as dynamic content scripting when opened in something like Adobe Acrobat/Reader. Some of that same scripting support, however, is also available in both Mozilla Firefox and Google Chromium ’s respective PDF readers, PDF.js and PDFium.

In the past, hackers have used this little-known Adobe feature to code simple games like Breakout and Tetris into PDF documents. But ading220 went further, recompiling a streamlined fork of Doom 's open source code using an old version of Emscripten that outputs optimized asm.js code.

However, modern browsers can unlock more features for PDF documents, as proven by new ports of Tetris and DOOM. Thomas Rinsma, a security analysist and developer, published a working demonstration of the classic puzzle game Tetris running entirely in a PDF.