That didn't surprise me at all. I always said, that Gamecube was a graphic whore itself. No other console back then throwed out more polygons per second then good old Cube. And look how far even Wii is pushed in it's early lifecycle stage - HotD Overkill, The Conduit... (But not much more then these games, shame!) And Wii is only Gamecube times 2! Consider how brillant games would look when walked all the way PS2 had gone from early ugly games to God Of War II! And all this with merely 40 watts per hour!
That's why I always whine about graphics on Cube an Wii, that's why I always growl at people talking about rubbish like Wii being poor. Sure, these where techdemos, but all was there the Conduit has to sell as possible on Wii: moving textures, bump, shadow, normal mapping, environment mapping, big textures, point lighting, yaddayaddayadda...!