well i'm 6 months late but hey
confusing error message, but the game is 32-bit so you need multilib enabled (https://wiki.debian.org/Multiarch/HOWTO) and 32-bit dependencies installed
totally understand not wanting to break your system, i can say multiarch is generally pretty stable. betting you're still missing dependencies, can check
ldd "10 Beautiful Postcards.x86"
for any "not found" entries, which you'll have to figure out how to source from the repos. google should be helpful for figuring out which packages you need for a certain library filename, and remember you need to install the 32-bit version (I believe that's ":i386" after the package name in the install command)
this is definitely a little complicated so idm, i'm just providing da information for you or anyone else who stumbles across this thread :)
