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
thanks for the tip but unfortunately that looks like a good way to bork my system
Okay, 30 minutes later....I did go through this hilariously full of pitfalls document. I followed it, and cross-checked with other tutorials/recipes online for ubuntu 18.04 and still no dice. bummer.
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 :)
I tried again and managed to get all packages installed, which incidentally was another 350mb. Anyway, even after all that, no missing packages, but when i tried to run i got the error: Couldn't find data folder.