Which game has the best physics?

You are severely underestimating what you can do with Flash and Scratch. Hell, you could probably do the same advanced physics calculations on a Commodore 64 - sure, it'll be unplayably slow and will almost certainly require a RAM upgrade, but at give or take >0.2 FPS you might be able to do the necessary maths on a 6502.

Scratch in particular is only actually held back by the blocks (which, despite being a good jumping point for inexperienced programmers, are clunky as all hell if you try to do anything more complex than an Atari 2600 game) and the fact that for some stupid reason the Scratch Team insists on capping it a 480p 30FPS just to maintain backwards compatibility with the days when it was literally Flash-based. In fact, if you use the TurboWarp compiler instead of the Scratch Team's rubbish interpreter then it becomes actually fun to use as a result of the greatly improved performance. You can also bump up the resolution for a better image. If someone makes a text-based editor for TurboWarp, it'll become more about working within the limitations than having to put up with that nightmare of an IDE (I also think it would be useful for educators to prepare learners for real programming, but that's for another day).