The "RPG Game" is hard to judge since it was produced over "multiple turns". The impressive version would be if it basically got a working game on the first attempt, and the prompter gave some follow-ups to tweak feel and style.
However, I think what actually happened is that a skilled engineer made that game using codex. They could have made 100s of prompts after carefully reviewing all source code over hours or days.
The tycoon game is impressive for being made in a single prompt. They include the prompt for this one. They call it "lightly specified", but it's a pretty dense todo list for how to create assets, add many features from RollerCoaster Tycoon, and verify it works. I think it can probably pull a lot of inspiration from pretraining since RCT is an incredibly storied game.
The bridge flyover is hilariously bad. The bridge model ... has so many things wrong with it, the camera path clips into the ground and bridge, and the water and ground are z fighting. It's basically a C homework assignment that a student made in blender. It's impressive that it was able to achieve anything on such a visual task, but the bar is still on the floor. A game designer etc. looking for a prototype might actually prefer to greybox rather than have AI spend an hour making the worst bridge model ever.