Sure Why not? The engineers at google and open ai or wherever else trained the models but they didn't teach it how to do anything it does because they don't know how to teach it to do anything it does. So yeah the achievement is on the neural network.
Many people gave the likes of alpha go achievement on super human Go play.
It is? OK, tell them to completely clear the model of any angry bird original and clone code, data and assets that it scarfed from the Internet.
It can retain scarfed definitions of angry and bird as well as scarfed information on making a 2D video game.
Then tell the model to create the game and see what if anything it comes up with.
Most of the Angry Birds mechanics in this demo come from the underlying Matter 2D library. Relevant demo here: https://brm.io/matter-js/demo/#slingshot
Honestly, that's most of the code part accounted for.
The bigger question is the graphical assets. The developer shared their prompts for those here: https://twitter.com/javilopen/status/1719363587351740711
Some of them make no mention of Angry Birds - "Wooden box. Large skeleton bone. Item assets sprites. White background. In-game sprites" - but others do: "Item assets sprites. Wooden planks. White background. In-game sprites. Similar to Angry Birds style"
My hunch is that a skilled image prompter could still get to results that were right for this particular demo even with a model that had not seen Angry Birds assets before.