The title says 'in 25kb on a graphing calculator'. The only way it's "amazing" is if you know what a graphing calculator is, and if you know that, then it's pretty obvious that the title is a mild form of poetic license rather than a sensationalist attempt to mislead. And really, when people think of "Portal physics", for the most part they think of 'a hole between two non-adjacent surfaces you can travel through', not 'a realistic 3D world where objects behave according to newtonian physics', because the latter is a dime a dozen.

Honestly, how many people who know what a graphic calculator was would seriously think that they "remade the Source engine", misled by the 'sensationalist' title?

The technically fascinating aspect of implementing narbuncular/portal physics is the optics of looking into a portal, not the trivial translation/rotation of passing through a portal in a platformer sideview.

You don't think that ionforce is over-egging the criticism pudding by throwing in inferred claims about graphics, too?

I find it ironic that such a tactic should be used in a criticism that strongly applies the 'shameful' label.

You're right that it is ironic. It's ironic the same way bigots say that liberals are being intolerant of their beliefs.