X0r_jmp, the anonymous leaker(s) behind the cavalcade of prototype Dukes Nukem revealed to us over the past year, has branched out to another beloved ’90s shooter franchise, Blood. On January 4, x0r_jmp made Blood’s in-progress source code from a year prior to its release available to the public.

Developed by Monolith, who would go on to create FEAR and the Shadow of Mordor series, Blood was created in the same Build Engine as Duke Nukem and can thus be seen as a sort of sister game. Blood has the lightning-fast movement and sprawling, maze-like levels common to shooters of the time, and also differentiates itself with a unique arsenal (sticks of dynamite? A hairspray and Zippo lighter flamethrower?) as well as a gothic, horror-adjacent atmosphere.

Unlike prior releases in the Year of Duke Nukem and Duke Nukem-Adjacent Leaks, there doesn’t seem to be anything actionable for players or modders here⁠—Blood has had excellent source ports like NBlood and Raze for years. The real treat is purely academic: this archive is a window into the development of a PC classic, and can provide insight into Monolith’s creative and technical process.

For example, the BLOOD.txt file in the archive contains a changelog for the in-progress game, with patch notes dating back to January 1995. That first entry has a round-up of the enemies implemented in the game up to that point, alongside a brief summary of their state in the build. Describing Blood’s riff on the Evil Dead disembodied hand enemy, the log’s writer declares it’s “Way cool!” I just find it neat to see the creator’s fingerprint in this way, especially when it’s so endearing and completely unaffected.

Similarly, the ’90s FPS Twitter fan account Build Engine Aesthetics found complaints and snarky digs at Build Engine architect Ken Silverman buried in the comments on the build’s code: “Call this function periodically to fix all the problems Ken causes by rearranging the database with abandon,” one comment reads.

However x0r_jmp keeps uncovering these classic shooter artifacts, I find them priceless, a peek behind the curtain of gaming history that just feels precious and unlikely. If you’d like to peruse the Duketrove + Blood yourself, you can find the files on x0r_jmp’s Rentry.co page.