Actor Allusion: They're everywhere, right down to some of the death scenes.
As Himself: The party guests played (an exaggerated version of) themselves.
Creator Cameo: Josh Flanagan, the series' creator, appears in Chris' blackmail photo, in his "Jerry BJ" costume.
Flawless Victory: Out of over 50,000 participants, only one person correctly guessed the survivor, the killer and the murders of seven of the victims (in total, 16 correct answers).
Foreshadowing: A very meta example: In the first episode as Burnie reads the poem and the guests are being shown, Gavin mentions how it would be too easy for the guests to be killed in the order they appear. Right after this, Adam appears on camera for the "One ran out of air" line, and ultimately dies in episode 6 - so far they have been the only victim whose time of murder could have been predicted from the first episode (Josh Flanagan confirmed this to be true after episode 6 aired). Furthermore, the last two lines of the poem show Barbara and Ryan before cutting back to Burnie saying "And then there was one".
Lying Creator: In the Let's Play Grand Theft Auto V episode "Things We Did", Geoff off-handedly mentions that Ryan would be the one to die in Episode 6 with Ryan playing along. As you can see, they were clearly lying.
Well, half-lying. We do get to see Ryan's death portrait in Episode 6, for all of 5 seconds...
Of course, keeping in mind how episodes of let's plays tend to be recorded ahead of time, and it's unlikely employees who aren't working on the show get to see episodes early, it could be that they were just making a guess from an earlier episode.
And Ryan ends up the Sole Survivor, so Geoff was clearly just making a wisecrack.
Real Life Writes the Plot: Due to the filming of Lazer Team taking place around the same time, some of the actors in the series who play major roles in the film are killed off fairly early on, notably Michael and Gavin, the first two deaths of the series, with Burnie following suit not long after.
After episode 5 aired, Josh Flanagan (the creator of the series) revealed that there would be a change to the poll leading up to episode 6, and that two possible murder victims & murder weapons would be accepted as correct rather than just accepting the episode's actual victim and weapon. The reason for this is that, whilst only one character would die in the sixth episode, Josh realised that apparently there was enough evidence in the previous episodes to support a plausible theory for another character's demise in the same episode, and he didn't want to cheat those who had come to the wrong conclusions based on the evidence provided. After the episode aired it was revealed that Adam dying by a sting from a blue ringed octopus was the red herring answer accepted in the poll.
What Could Have Been: As revealed by a scrapped Death Portrait image, an earlier draft of the script had three Gavins instead of the two that made the final cut, which, according to Josh, "would've been glorious". Remnants of this still exist in the script, with Burnie's line to Gavin at the party "Stop bringing one and one fifths more people to this party than you're supposed to!" after Lindsay suggests that a clone should count for only 3/5ths of a person.