Well, at least the 18 I put in were all correct, that's something
Now for my gripe: I am appalled that the Witness was not in this quiz! That's like the gold standard for a puzzle in the game, it's got more than 200 of them.
Or what about Banjo Kazooie/Tooie ? You collect jiggies which are actual puzzle pieces which you then use to complete puzzles so you unlock levels to play...
So yeah, Codebreaker. That one was a doozie. The only permutation of keywords that made a screenshot appear for me was "atari 2600 puzzle game". Singular form. As soon as you pluralize to "games", poof - gone from the search results. I was early on cursing the fact that the screenshot had so little detail to it, just a couple of squares. But that actually made it stand out because I can't actually find an Atari 2600 game with less detail to it than Codebreaker. Just had to find a screenshot with almost nothing in it.
Chromagun was a fun one. I didn't know the game at all but the Portal hint made me google "games like Portal" and hey presto, top search result.
Murder by Numbers I found by complete accident. I was googling every permutation of "puzzle game flying robot" I could think of and zip, nada zilch. I pretty much figured I would never figure out that game. But then I was trying to find what turned out to be Picross and for some reason I started to search for "numbers puzzle video game" even though there are no numbers in that screenshot. And then I saw the flying robot, right at the top of the search results. Go figure.
Did anyone not know Silent Hill but still managed to find out based on that screenshot which does not actually show the game itself? I've played the game a million times so I already recognized it by the font alone, but I felt a little sorry for people who were unfamiliar with the game