Some great-looking PSP screens

[OB1]

Well, essentially, if Metroid Prime was downgraded to 30fps then yes, they could double the polygon count (etc.).

Which is why a lot of games DO run soley at 30fps and don't attempt higher than that, as they'd prefer to look pretty in screenshots than fluid in motion. It's something that (in most cases) just represents to me a poor attitude of videogame developers. IMO, all games should run at 60fps, regardless of how much the static screenshots might suffer because of it.

There are some exceptions of course. A game like Splinter Cell would be quite difficult to run at 60fps (on current hardware..) due to it's advanced lighting techniques. But with that possible exception, I would GLADLY take a drop in textures and polygons to have a much more fluid framerate.

If game engines were as flexible as you are suggesting then there would be no need for talented programmers in the industry. All you'd have to do is double everything over and over, optimizing things for each new hardware. If a game pushes 5 million poylgons per second at 60 fps, you are not going to be able to double the poly count at a steady 30 fps. Now I'm not a programmer myself but I work closely with one on the games that we're making and I know a number of programmers who are either working on getting a job in the industry or are already making games for people like Rockstar. For instance, we're using a simple 3d engine for our upcoming platformer (though you won't be able to tell that it's 3D, much like Four Swords Adventures), and my friend (who built the engine from scratch) has shown me some tests that he's done so far that gives me an indication of what kind of limitations we're working with, and how it all works. He gave me a realistic poly and texture "count" and I actually asked him if it could all be doubled with the framerate halved, because I thought as you do. His answer was of course "NO". It's not nearly that simple, though we wish it were. If you want me to get into more detail I could ask him to write up an explanation for you. :)