survival mode

Noun

survival mode (uncountable)

1. The situation of being focused purely on surviving, without time for recreation etc.
   • “Frank-- Frank, we are no longer in relaxing mode. We are now in survival mode.” “Pl- Will you stop being so dramatic? Wait a minute. Wait a minute. Where's the rum ham?”2011 September 22, Dave Chernin & John Chernin, “The Gang Goes to the Jersey Shore” (8:32 from the start), in It's Always Sunny in Philadelphia, season 7, episode 2, spoken by Mac (Rob McElhenney)
2. A gameplay mode in which the player attempts to survive as long as possible in a single session presenting increasingly difficult enemy waves or challenges.