I just considered (after decades of reading and thinking about Godot) that Vladimir’s nickname could be read “Did I?” – this seems sufficiently appropriate for the “mental” one of the pair that I wonder if Beckett might have intended that play on words. “Gogo” is pretty obvious, I would think; hence his foot problems.
I also love the way Beckett critiques the audience – rarely in other works, but several times in Godot. Breaking the fourth wall is one of my favorite conceits, although it has to be done very carefully or it’s just a gimmick (I always felt there was too much Godot in Rosencrantz & Guildenstern Are Dead).
Right at the beginning, about 8 pages in, Estragon turns his back on the audience, “Charming spot,” and then faces the audience with, “Inspiring prospects.” Then he turns to Didi and says, “Let’s go.”
In Act II, when blind Pozzo asks, “Is this by any chance the place known as ‘the Board’?”, Didi never heard of it, and Gogo says, “It’s indescribable. It’s like nothing. There’s nothing. There’s a tree,” to which Pozzo replies, “Then it’s not the Board.” In the UK, of course, everyone knows that the Elizabethan actors all “trod the board.”
But at the beginning of Act II Gogo and Didi really attack the audience:
Vladimir: Where are all these corpses from?
Estragon: These skeletons.
Vladimir: A charnel house! A charnel house!
Estragon: You don’t have to look.
Vladimir: You can’t help looking.
Vladimir: Try as one may.
A charnel house is, appropriately, a place where disinterred bones are stored, when they are exhumed to make room for the more recent dead. Not unlike a theatre with an unresponsive audience.
I should also provide a link to a brief photographic homage to Godot that I created a few years back: https://vimeo.com/16134190.