What about an
Escape the Village (a.k.a Left & Dead or Call & Duty medieval c-RPG):
After spawning, players have to cross the map to reach the exit/checkpoint/flag. Random bots would spawn at random places (to avoid camping techniques) continuously.
The multiplier for the next round would depend on how many players survive.
Players would choose tactics between rushing (at the risk of being vulnerable to archers and cavalry) or progressing more slowly in an organized/turtle defense (staying longer on the map).
As long as one
survivorplayer is alive (even though a part of the team has reached the exit), the round is not over. Will they move back to help him? Or let him on his own, risking to lose a teammate and thus a mutiplier?
Better with big maps/cities/fortress/mazes/hills everything that makes progression difficult.
Even funnier if players don't spawn at the same point.