Random collection of thoughts:

1. GOG's Linux installers are basically zip files, so you can unzip them even if the embedded gtk stuff does not run.

2. ToME is open source, so it should be possible to compile it for ARM, but it probably would require a huge amount of modifications to the OpenGL parts. And the RPI might be too slow to run it even then.

3. I wonder if HyperRogue would compile on the RPI.

The preposition in the original question: "What's your favorite game on Rasberry pi" — "on" — makes no assertion about the nativity of the game one way or the other, so your criticism is invalid.

In addition, I'm pretty sure many open source games can be compiled to run natively.

Been awhile since I had RetroPi on mine, but Descent and Wipeout was my two favourites.

Are they DOS games?

Both for DOS and PSX, but to my knowledge only Descent (and its sequel) have a source port.

Tu quoque fallacy/weak strawman. The problem is EVERYTHING on the system is something from something ELSE. Which is precisely WHY it's a slippery slope. It's tantamount to saying "what's your favorite SNES/Genesis/TG16/Source Port/<Insert any game system here>?" (Though, that would be a much better question) as it plays a ton of different systems, rendering the logic of the question pointless at best. None of the games can be attributed to the system, only the systems they emulate. Nice try though. C-.

So, your criticism is that the question can't be asked because the Pi is an emulator? Sounds like legalistic rules-lawyer mumbo jumbo. And —— since everyone contributing was able to make the apperceptive leap you seem to be implying is too broad to broach —— moot. But, as you say, to be completely correct the phrase ought to have included some implication of the process of emulation … but I'm not sure anyone else cares about it for the purposes of the discussion.

Does every SNES/Genesis/TG16/source port/et hoc genus omne actually execute on the Pi? Are there extra customizations required? Now that is worth talking about.

"The logic of the question" seems to have had enough impetus to start and propel the contributors in earnest discussion, after all. :)