Bonus stage either have no enemies or hazards, or replace the normal penalties for being struck by enemies or hazards with simply being thrown out of the bonus stage.
Many bonus stages need to be activated or discovered in some manner, or certain conditions must be satisfied to access them.
Other bonus stages have no end to reach, the player must simply survive as long as they can before inevitably failing at some point.
Namco's 1980 arcade game Rally-X was one of the first to feature a bonus stage.
Other bonus stages use the same gaming paradigm as the rest of the game, as in the car smashing bonus stage of Street Fighter II, or the bonus stages in Super Monkey Ball, where players collect bananas to earn extra points and lives.