The Backrooms Deluxe 2 is a spin on The Backrooms Deluxe with new features such as:

Modifiers

Mix and match positive and negative effects that give you more or less Deluxe Coins at the end of your run.

Much better multiplayer replication

The entire game has been rewritten to support a much more seamless multiplayer experience. 

More Achievements

The game has received more achievements, as well as support for non-Steam achievements (only in the game but don't affect Steam progression) for harder challenges.

Roguelite Elements

Since the original game, permadeath has been added, which adds a new element of challenge as well as being able to earn Deluxe Coins without having to do a full run every time. All players have to die for the run to end.