I have discovered that Urban Chaos was indeed meant to be multiplayer. And the Mucky codes you get from beating the levels are what you use to access them. by replacing the Semtex level (semtex.ucm) with an unknown level I found in the level data called "capflag1.ucm" I successfly accessed the Capture the flag level and sure enough there were split screens. Roper on the bottom Darci on the top. So how do I know the mucky codes are connected? Well when you complete the level it has the normal "Time Taken" and "Mucky Time" options, and under "Time Taken" it uses the tag "CODE: BCC1" BCC1 is a known mucky code. Therefore I theorize that by entering these codes into the F9 Chat option, you unlock the levels. The level is by no means finished. The programming is far from good and the textures are uncomplete which leads me to believe that the muck codes have been dropped from the game and cannot be used but it is possible.

ALL URBAN CHAOS PLAYERS STILL OUT THERE, PLZ RESPOND

Actually, that's not true. I'm good mates with Mike Diskett, I sent an email off to him asking if this was true. While it indeed was true that Urban Chaos was meant to be multiplayer, the mode was never supposed to be accessed via mucky codes. The mucky codes were just proof that you did a level in certain time, thats why they're all different. Multiplayer and some other nifty features were axed due to time constraints. This was Mucky Foots first game under Eidos and they couldn't afford to be late with it. Keeping those features in would have added at least another couple of weeks of debugging.