During the Halloween Event, decorations such as Jack-o-Lanterns could be found throughout the Facility including the DMR Control Room. Melting down the Dark Matter Reactor would result in the teleportation to a cutscene game, the player being tied up to a chair as a dark empty hallway could be barely seen ahead. A tall mutated penguin-like entity would emerge, armed with a chain-saw, monologuing about the players affects on global warming and remarking about the destruction of their home in result of QSERF being destroyed. The penguin would be revealed to be non-other than Pingu, who then kills the player.

During the Christmas event, decorations were also present, and the entire reactor was decorated as well with Christmas lights and tinsel. A cutscene was present upon reactor destruction, it did not matter if players escaped to the Tartarus Zone or were on/near the DMR during its destruction. The cutscene would feature a comedic telling of "Santa's Naughty List", with special versions being made solely for certain administrative and development personnel, non-specific users receiving a generic ending.

The update would also introduce presents, as well as themed such as the Obama Tree, and Bouncy Ball. These items would remain strictly as event items and would end up going unused after SST's reorganization in February 2020. The facility itself would be decorated with Christmas lights and various other decorations, the DMR itself being covered in lights with a massive Santa hat. Various portions of the facility were covered in "snow".

During the 2020 Christmas event, the DMR was decorated with lights and a massive Santa hat, and decorations were placed throughout the facility. A new green pipe was added (leading to the Heaven Tower obby, see below) and a large blue present (when clicked 500 times teleports surrounding players to the Stonky Snow boss battle, see below).

During the 2021 Christmas Event, the DMR, unlike previous years, was themed to resemble the 2020 Christmas Event boss, Stonky Snow. Like previous Christmas events, the facility was once again decorated with Christmas-themed festivities. The 2021 Christmas Event would also introduce a new boss, Santa Soup Can, a boss based off Valve's Team Fortress 2 Character, the Demoman. 

This was a large event, see the subpage.

Decorations around the facility but no major events. The mini events shop items and XLS mk2 has been brought back from last year's Halloween. Information on this can be found here. 

Chrismas decorations, including a Santa hat and Chrismas lights on the DMR, snow in many parts of the facility, changed elevator music, presents around the facility, and changed meltdown music.