Zeus - Can destroy almost any game. Unless playing against players who are really good at predicting.
Emmett - Even if you get no kills at first the carpet bomb at the end will get at least some.
1 - Dante inferno
2 - Pyramid Head
3 - Superman sorry that's from another game
best special 3 is for Sackboy far
dream come six new characters
Hmmm.... this is a tough one. I've seen a couple of Sweet Tooth players who were able to get 9 kills with their level 3 (this was before the patch BTW). However, I've also seen a couple who were only able to kill one single person. Same thing with Kratos. Sometimes, they get up to 6 kills, and sometimes, they only manage to get one. It all comes down to the skill level of the player basically, so I can't really decide what the best level 3 is at the moment.
As for worst level 3 though, I'll probably go with the screen clearers (Heihachi, Parappa, Toro, Spike).
Yeah that 9 kill count was me. Even after the patch I've gotten 3 kills per player, though it's much harder. As for that guy getting a single measly kill... that has also been me...
I'd say Sackboy, because all he needs to is touch the player to eliminate them. Plus you can use the provided gadgets from the prize bubbles to take them out as well (ex. RPG).
Side note: Heihachi's 2nd pretty good too. It's also ridiculously hilarious.