I think you're mistaken. The abstract says it's interactive, "We present GameNGen, the first game engine powered entirely by a neural model that enables real-time interaction"

Further - "a diffusion model is trained to produce the next frame, conditioned on the sequence of past frames and actions." specifically "and actions"

User input is being fed into this system and subsequent frames take that into account. The user is "actually" firing a gun.

?

I highly suggest you to read the paper briefly before commenting on the topic. The whole point is that it's not just generating a video.

Uff, I guess you’re right. Mea culpa. I misread their diagram to represent inference when it was about training instead. The latter is conditioned on actions, but… how do they generate the actual output frames then? What’s the input? Is it just image-to-image based on the previous frame? The paper doesn’t seem to explain the inference part at all well :(