[asveikau]

Off topic, XKCD should put the original publication date on the page. This one references specific years, and I could tell it's from 2009 after thinking about it, but doesn't hit the same way.

[nottorp]

I've never played enough Portal to get to the point referred to by the comic, but I get the idea.

And yes, I probably played Portal 1 a few years after Portal 2 was out.

[catlikesshrimp]

I tend to read this shortly after the strip, because I am that stupid. Also because there is no easy mouseover on android. https://www.explainxkcd.com/wiki/index.php/606:_Cutting_Edge

[renata]

m.xkcd.com lets you click for the alt-text.