Available to play
Doom-in-Doom
Runs a second copy of Doom on a wall inside unmodified DOS Doom II using a code-execution exploit.
What it does
kgsws found a code-execution vulnerability in DOS DOOM2.EXE and used it to load a Chocolate Doom port that renders to a texture inside the host game, effectively a cinema room showing a playable Doom. The same technique was shown running Heretic. The exploit work became the ACE Engine (latest v4, 2023-11-12, LGPL-2.1).
How it works
Arbitrary code execution via a DOOM2.EXE savegame/WAD exploit (later generalised as kgsws's ACE Engine) loads a Chocolate Doom port whose framebuffer is rendered onto an in-game wall texture
Requirements & limitations
Original DOS DOOM II v1.9 executable and WADs
Original sources
Evidence limits
Primary sources reviewed on 2026-10-08 (github.com, api.github.com, doomwiki.org, hackster.io, youtube.com). No independent catalogue play-test or binary safety review was performed.
Code and releases are linked, not hosted here. Game files and footage retain their owners’ rights.