From the "Play" option on the main menu go to the bottom one, should be "Daily Challenge¨.
This are very specific scenarios with timed features.
Basically you have to travel through it and beat the boss (The Concierge, which is the same of "The Bridge") in less than 4 minutes with 30 seconds
Weapons are fixed each day at the start (you can pick just one) and the upgrades scattered across the scenario are for the three types of skills.
If you want to go directly to the boss just follow the arrows with the skull.
However, I do not recommend to rush since you will be very weak and unarmed to be able to defeat it.
You can retry as many times as you want in a day, remembering the locations of the map (it does not change or randomize during the playthroughs for each day).
The idea of it is to beat 5 of them to earn some special items.
BTW: I did the challenges but due the achievement bugs I don't have it unlocked, at least yet.