Every day, each player is given five new random daily missions shown in the upper right corner in the menu. Completing these missions is voluntary, but their completion during that day will be rewarded with the reward shown next to the mission description. The missions, whether completed or not, get replaced with new ones when the day changes according to EST or EDT (UTC−05:00 or UTC−04:00). This time is shown on the official website of Brawl Busters.
The first two missions are always rewarded with 1000 BP. The missions can be about killing/assisting in killing 10 busters or winning twice/playing five matches in a certain game mode, for example.
The third and fourth missions can be rewarded with 2000 BP or a Purple or Red Box (1 or 2). These rewards depend on the mission. For example, missions about slaying a certain number of zombies with a certain class are always rewarded with a purple box, while missions about killing ten busters of certain class are always rewarded with a red box. These missions can also be about getting certain medals, excluding the Triple Crowns and Immortality medals.
The fifth mission always has a random reward (shown with a question mark): either 3000 BP or only a blue box. These two rewards are approximately equally probable. The mission can be about winning a Boss Battle or Zombie Survival match with difficulty set to hard, finishing one or two busters with poison, hand bombs or bombs or getting a Triple Crowns medal/Immortality medal/Perfect Victory.
The box rewards are very small in value compared to the BP rewards. Boxes can be bought from shop with less than 250 BP and the selling price of an unopened box is only 15 BP. This makes the third and fourth missions often uninteresting to concentrate on, and lowers the expected value of the reward of the fifth mission below 1750 BP (assuming 50/50 chance).
Some of the missions cannot be completed in certain game modes, although that is not explicitly stated in the mission descriptions. For example, one cannot complete daily missions in Glow Control or Zombie Infection game modes. Furthermore, some missions that can be completed in Team Deathmatch cannot be completed in Ranked Matches. Another common source of situations, where missions surprisingly do not get completed, is the misconception that a Double or Triple Crowns medal will do when a Single Crown is needed, or that Triple Crowns will do when a Double Crowns medal is needed.