This seems more a critique on the particular model (as in the resulting diffusion model generated), not on diffusion models in general. It's also a bit misstated - this doesn't require a working car on the road to do its job (present tense), it required one to train it to do its job (past tense) and it's not particularly clear why a game engine using concepts gained from how another worked should cease to be a game engine. For diffusion models in general and not the specifically trained example here I don't see why one would assume the approach can't also work outside of the particular "test tracks" it was trained on, just as a typical diffusion model works on more than generating the exact images it was trained on (can interpolate and apply individual concepts to create a novel output).

my point is something else: a game engine is something which can be separated from a game and put to use somewhere else. this is basically the definition of „engine“. the above is not an engine but a game without any engine at all therefor should not be called „engine“.

Interesting point.

In a way this is a "simulated game engine", trained from actual game engine data. But I would argue a working simulated game engine becomes a game engine of its own, as it is then able to "propell the game" as you say. The way it achieves this becomes irrelevant, in one case the content was crafted by humans, in the other case it mimics existing game content, the player really doesn't care!

> An engine would also work offroad.

Here you could imagine that such a "generative game engine" could also go offroad, extrapolating what would happen if you go to unseen places. I'd even say extrapolation capabilities of such a model could be better than a traditional game engine, as it can make things up as it goes, while if you accidentally cross a wall in a typical game engine the screen goes blank.

The game doom is more than a game engine, isnt it? I‘d be okay with calling the above a „simulated game“ or a „game“. My point is: let‘s not conflate the idea of a „game engine“ which is a construct of intellectual concepts put together to create a simulation of „things happening in time“ and deriving output (audio and visual). the engine is fed with input and data (levels and other assets) and then drives(EDIT) a „game“.

training the model with a final game will never give you an engine. maybe a „simulated game“ or even a „game“ but certainly not an „engine“. the latter would mean the model would be capable to derive and extract the technical and intellectual concepts and apply them elsewhere.

> Here you could imagine that such a "generative game engine" could also go offroad, extrapolating what would happen if you go to unseen places.

They easily could have demonstrated this by seeding the model with images of Doom maps which weren't in the training set, but they chose not to. I'm sure they tried it and the results just weren't good, probably morphing the map into one of the ones it was trained on at the first opportunity.