i haven't tried any of the games you've listed, and the other gameszhero games i played so far have worked just fine with newgrounds player.
but when they don't, trying to use ruffle should work.
unless it's a specific case, medals should work with it as well, in general
picking this back up because it's related, although i'm not sure if it counts as a "broken medal" or as the game itself being broken.
continuing playing gamezhero games every now and then. can confirm that 99% of them don't work in NG player because it never gets past the loading screen, but they seem to work fine with ruffle, and medals are also awarded just fine.
a handful of them have extra issues where the games don't work even after loading, but i'd rather play through all of them and make a comprehensive list rather than dropping only a few titles at a time; though this is a separate case.
i've been trying their most recent submission (of the ones with medals): https://www.newgrounds.com/portal/view/607279
the game runs fine, except there seems to be an issue with the game's physics, where items that are supposed to "overlap" one another are treated as individual entities.
i've confirmed that's the case after looking up a walkthrough of the game after finding myself stuck on a level, and seeing it's behaving completely differently than expected.
in particular, there's levels where you encounter seesaws that you need to cross over; except in my case, the plank you're supposed to walk over is completely underneath its fulcrum (a solid object).
for some reason these sections also seem to have a lowered ceiling, so it ends up effectively becoming an impassable wall.
you can use other rats to push most of them over the obstacle, but the remaining one can't jump over it because of the lowered ceiling, and landing on top of the fulcrum makes you slide back down to the side you started on, before you're able to act again.
expected behavior (from walkthrough):

actual behavior:

as this seems to be an isolated case (i haven't seen anyone else anywhere mentioning this problem), i'm not sure if it's a me issue, or if there's a solution for it. i also have no clue what caused the game to behave differently in the first place.
however, as there's no feature to skip levels or something to a similar effect, these levels are virtually impossible to clear.
TL;DR game physics broke, somehow. cause unclear, but the game is unclearable in its current state; thus, the medal for beating the game is effectively broken (even though it probably unlocks just fine)