Every single line of code you have to add or change is going to decrease the likelihood of this ever happening It's a collaboration on an art forum, no need to be thinking about new and complex game modes, just do art. Someone on the previous page mentioned taking an existing level and just remaking it with a new aesthetic…
Along with remaking JUST art, we could take a source game ('cause you know valve is great about this kind of stuff) and just remodel EVERYTHING. Not change the story, or any code, just change the how the game looks on the outside. Specifically for this, i think HL2 would be perfect.
I like how someone said we should just take all the code and gameplay of Left 4 Dead and make it our own. A small room fighting off wave of zombies. What if we put all the L4D2 characters in the future and fighting off waves of Robots. Or vice Versa. Robots fighting Zombies. ..maybe it's cause I love Robots or Zombies.
My 2 cents is that the others have it absolutely right. Make a simple DM game using UDK, and go from there. One idea though if you actually want to add a bit of variety into the mix is possibly changing the CTF code so it's a capture and hold deathmatch. There's 1 flag, and you get points for every second that you hold the…
Sorry if this seems short and all (im currently sick, and it sucks :( ) I was thinking maybe a jack the ripper-esque(gothicy, dreary london) art style/timeline, and the game mode could be something like: Citizens(5 or so maybe) vs a Killer, however the killer would appear to be one of the citizen avatars to the citizen…