I had suspected it'd be the case, but I can confirm that #SDL applications that do not require hardware acceleration do run nicely in #Xephyr under #OpenBSD. I was able to play some #IndianaJonesAndTheFateOfAtlantis in #SCUMMVM in my sandboxed environment & user at the end of today's #twitch stream. Sound and all!
I _finally_ fixed my configuration to install my primary user's #sndio cookie for my sandbox user. Must be 'rw' for the user only, otherwise sndio will "fix" and gen a new cookie.