Seems like they technically went a bit farther than mocking game footage (but barely). A 2001 demo of sort, that’s probably close to what they showed at E3 that year, was leaked in 2022.

It’s “playable”, in the sense there are quite a few maps you can explore and player physics and weapons are functional. But there is basically nothing to do, in particular no enemies at all.

Anyway, DNF has been a fun ride all these years, and the best part is you didn’t even have to play it. The pathetic attempt from gearbox to salvage it just gave a final punchline to the whole joke.