A lot of them could be inferred from what the code is doing. For example, PHP and Perl are sometimes really hard to distinguish, but I was able to get PHP right by deciding that "this ain't what a Perl hacker would write". Same with Ada v. VHDL.
Missed Kotlin here too. I also missed one where I guessed Haskell when it was actually Prolog.
I feel like this quiz was much more about how much you've dabbled at surface level in various languages, enough or not enough to remember specific details to aid in process of elimination. For example, I knew what GLSL stood for, so the picture was most definitely not GLSL. And I had at one point written Scheme and looked into Lisp enough to guess that it was Clojure and not Lisp. And I remembered vaguely enough that Objective-C still uses C-like pointer notation, for example. And I remembered enough of computer engineering class to immediately identify that the VHDL question's code fit the use case despite not having written a line of VHDL (or Verilog) ever.
A lot of them could be inferred from what the code is doing. For example, PHP and Perl are sometimes really hard to distinguish, but I was able to get PHP right by deciding that "this ain't what a Perl hacker would write". Same with Ada v. VHDL.