If you have ever played crash bandicoot, you've played a level where some large boulder/creature has chased you. Because the physics of the killball allow it to rolll along a path, you could creat a map where 1 or more killballs are chasing the player. In the first CB chase level it was a boulder, and every now and then you would reach a safe cave. Once you left another boulder would chase you. At the end of the level you cross a bridge. Once your over the bridge falls and the killball with it. I wouldnt know how to do the caves, but the bridge could be fixed explosions you could shoot once across. The final area could be a hill that the only survivor captures. I suck at forge, so anybody who wants this idea can take it.
The difference would be that in Crash, you're not in first person, you can run away from it and still see it behind you. In halo you'd just run like hell not knowing if you have to run even faster, or whether you can sit and take a breather while enjoying some tea.
True, perhaps the killballs can blow up stuff? If so you could here explosions going off behind you if you were about to die. You could also take a chance and try to look behind you. You could also here people in the game dieing if you were in the front.
Even then, what would the objective be? How would people score, and it really wouldn't feel like Crash unless you were running in third person, at the camera, away from a large boulder type thing.
To be honest it doesnt have to "feel" like crash for it to be inspired by it, and a player doesnt particularly have to know how far away the kill ball is. This is actually a nice idea I might create something from this some day.
Like I said, KoTH. The ending safe spot is a hill, once you reach it you get a point and the round ends. Also, Ive already stated numerous ways you could keep track of the killball.
I'll try it if I get a chance. I'll give you credit when i finisih it. Also, I'll post a link to it here. Since I don't have a lot of time on my hands, don't expect anything soon.