By the way I'm almost done with updates ;^^ they've been something of a project because I went like three months without running them which is way too long. I think they're basically done now though aside from some housekeeping and things. (I feel obligated to note that Linux on the desktop isn't always this involved to maintain, just Gentoo specifically. ;^^ ) I'll let you know what happens once it's all totally done.
For what it's worth, I ran the browser version via Firefox on Kubuntu and it seems like everything works 100%[1]. I'm satisfied with the four to seven[2] endings I found, anyway. :)
I didn't try the downloadable version with Proton.
[1] I guess you can never technically be sure, if you don't have a baseline for what the full functionality looks like.
[2] Depending on how pedantic you want to be on what defines a "different ending".