A few days ago I saw this video: https://www.youtube.com/watch?v=3EPTfOTC4Jw

Apparently the "64bit bug" can't be reproduced nowadays. The first generation of Intel's Itanium processors had their floating point unit rounding differently from what we're used to on x86 or x64. Interestingly the second generation had an instruction to switch floating point mode to the x64-like behaviour, so Space Cadet would possibly also run on them.

Microsoft seems to have made some effort to port it, but ultimately decided to kill it.

As far as I knows the 32 bit version runs fine on a 64 bit system (and had only x64 existed, I would have assumed that MS would just have shipped the unmodified 32 bit version of SpaceCadet - but for Itanium they needed to try to port it.) I can't verify, however, since I currently don't run Windows on my Laptop.