MadWorld is not 16:9, it's just a damn bad PAL-port by Sega with PAL-bars like in the 90's. That's very poor work by Sega.
But there are indeed games that are 16:9 only, it's not just 360 and PS3 it's on the Wii too.
But there are indeed games that are 16:9 only, it's not just 360 and PS3 it's on the Wii too.