The full theme song includes the lyric "The game sucks so bad he makes up his own words". This is set to a clip of the Nerd saying things like "fuck rats" and "fuck farts"...but if you look at it as referring to the time he had to make up a new swear for his Godzilla review, it makes a lot more sense.
On more than one occasion, the Nerd has used the phrase "It's like puking on a pile of shit!" to describe when his situation has gone From Bad to Worse. And in the Toxic Crusaders episode, he vomits at the sight of Lloyd Kaufman taking a dump on the cartridge. In other words, puking on a pile of shit.
In his Schwarzenegger Games review, there's no intro. At the end of the review, we find out why. The guitar dude is dead.
Don't worry, he comes back to life in the Ikari Warriors episode.
Invoked with Super Mario Bros. 3. James speculates that the reason the game is so difficult is because it was a product forged by the Devil and gives sound, if not out of reach, theories on why. One of those theories is that the seven sons of Bowser represent the Seven Deadly Sins.
This very site seriously considers Bowser's children to be designed after the Sins, as detailed on the Mario Bros. character page, so the theory certainly resonates.
He called the "Wally Bear" hotline in 2006 and it still worked. He's immediately creeped out because it's still being maintained.
According to YouTube commentators, the line was finally shut down around 2009.