Accidentally Accurate: In "LP Mario 64...very slowly", the duo joke about what would have happened if the Nintendo 64 really was as slow as the LPer's emulator made it look like. One of their remarks is how it had state of the art graphics and only 2 MB of RAM. This isn't very far off from the truth — the N64 had 4 MB of RAM without the expansion pack, yes, but it used high latency Rambus DRAM which made it a huge bottleneck on the system.
Colbert Bump: Diabetus refers to this trope as the "Retsu-Bump" at the end of the riff on Urban Runner, jokingly suggesting that the game will get a sequel because they made fun of it. Of course, there actually have been legitimate examples of this trope in regards to the subjects that they've parodied.
Sir Ron Lionheart's subscriber count skyrocketed after Slowbeef and Diabetus riffed on him. Subsequently, Chip and Ironicus made a video about how great he is, without so much as a hint of irony.
In "Metroid Machinima Makes Me Maddeningly Miserable," there's a crack along the lines of "I love how the tags include 'General Dysisa,' like someone's going to be searching for that." The creator of the video later commented that there was a sudden spike of people finding his video by searching for "General Dysisa."
Cornshaq is also enjoying his newfound popularity as an LPer, thanks in part to his badass reputation encouraged by the Retsupurae guys. While he has slowed his speech since then, he has beaten a lot of ridiculously hard games seemingly with ease.
During the Darkseed wrongpurae, Slowbeef mentions he emailed Mike Dawson about the game, but accidentally insulted him by mentioning he was making fun of Darkseed. Given how many people watched the video, it makes you wonder if Mike Dawson got hit with one of these.
Everything related to someone named Mike Dawson got hit with one after the Darkseed 2 longplay.
After the Crappy Pasta episodes featured Diabetus playing Mega Man Unlimited, it caused a small surge of Retsupurae fans to download it.
slowbeef: I think the Doug Walker video could've gone a lot better. Honestly, the source material was rough to begin with (it's soooo boring once you get past how bad it initially is) and Psychedelic Eyeball did a way better job.
Diabetus: The Nostalgia Critic RP wasn't good and we should've either scrapped it or gave it a 2nd take or done it with Chip and Ironicus
"Fat Fuck" has also been used to describe a number of the fatter people who have been riffed on, such as BigMastadon and Velos.
God Never Said That: A number of people have been lead to believe that the crew absolutely hate anyone that they riffed on who make money off of their Let's Plays. In Retsutalk 9, they explain that this isn't the case, and they don't hold it against the users (unless they are PewDiePie).
Also in Retsutalk 9, slowbeef and Diabetus both say that they don't actively hate The Nostalgia Critic like a number of viewers have argued, and state that he's probably funnier in other videos.
Hey, It's That Guy!: Both Slowbeef and Diabetus are well-known in the Let's Play community—the latter for his LPs of Battletoads (and Battlemaniacs, the sequel) and the former for doing the first known video LP (the concept described as being like a DVD commentary on a movie done by someone who had nothing to do with its production) of The Immortal. Also, Slowbeef, as mentioned under the Self-Deprecation entry, was involved in the translation patch for Policenauts.
Other recurring third members like Psychadelic Eyeball and Dave_O are popular L Pers on the SA forums. Especially noticible is Shmorky from some of their early videos who does animations for Something Awful and co-comentates with SA founder, Lowtax's own L Ps of horrible flash games.
There's also a large amount of Retsupuraes that have disappeared from the main channel, although they can still be found on alternate sources or reuploaded by other viewers. Most of their missing episodes involved footage of the actual people they mocked, which they removed due to a new Youtube policy.
Mean Character, Nice Actor: Despite the many nasty things he says on video, slowbeef seems to be a fairly nice guy in real life. According to him, he's even taken down a couple of RP videos because the original uploader asked politely.
Retsutalk in general shows that the people behind the accounts are actually pretty nice guys.
In Retsutalk 17, Slowbeef said in a quiet, friendly voice, "If our RPs genuinely hurt you, please, contact us." He then goes on to tell the story of a Pokemon video they removed because the author said in a very nice and friendly way he was trying to build a community and didn't want the kind of vitriol RP brings.
The themes that are used as bumpers for Retsutalk are also this - with the exception of the brief Battletoads "Level Complete" theme that plays in some videos.
Talking to Himself: The "Video Game Therapist" short has Slowbeef playing both the titular therapist and his patient.
Vaporware: Part 2 of Billy MC's let's play of Double Dare. Slowbeef has stated they'll never make it, as he and Diabetus didn't think the Part 1 RP was any good anyway.
Diabetus stated that he and slowbeef scrapped the idea of doing the final Jack French Retsufrash.
Why Fandom Can't Have Nice Things: Slowbeef and Diabetus discourage their fans from harassing the people they riff on. After their fans continued to ignore their demands, the main channel no longer has a comments section and, with this video, the original video's owner had his/her name censored. This is also why the channel went into Network Decay with traditional videos being produced at a slower rate in favor of Retsufrashes and Wrongpuraes.
The original video is actually here. Despite not wanting their fans to find the video and bash on the creator, slowbeef and Diabetus offer enough to go on that it was quickly tracked down by some RP fans. After the predicted bashing by said fans, the creator, Xtrmn8r123321, stated that he "faked" the video, and people would take him more seriously next time. Later, he created a video response where he stated he was going to kill himself because of the negative backlash of the Contra video.