It seems to behave similar to https://forums.castlestory.net/discussion/6990/linux-bug-start

#0  futex_abstimed_wait_cancelable (private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x7fffc17990c0) at ../sysdeps/nptl/futex-internal.h:323

#1  do_futex_wait (sem=sem@entry=0x7fffc17990c0, abstime=0x0, clockid=0) at sem_waitcommon.c:112

#2  0x00007ffff7c58278 in __new_sem_wait_slow (sem=0x7fffc17990c0, abstime=0x0, clockid=0) at sem_waitcommon.c:184

#3  0x00007fffc1478212 in mono_sem_wait () at disobedient_sheep/linux_content/disobedientSheep_Data/Mono/x86_64/libmono.so

Tried the sig handlers suggested in that thread, which got me a little further before crashing.

#0  0x00007fff93549a45 in FMOD::Studio::EventInstance::stop(FMOD_STUDIO_STOP_MODE) ()

    at disobedient_sheep/linux_content/disobedientSheep_Data/Plugins/x86_64/libfmodstudio.so

#1  0x00000000400d62ab in  ()

#2  0x0000000002261800 in  ()

At this point not too sure what to do, apart from seeing if replacing any libraries from Steam might help - obviously can't just use Steam version libs since I hadn't bought it from there.  Anyway, it clearly needs some work to run.  If I find anything on their forums or whatnot, will report back here.