The system requirements are very minimal (see "For running Unity games" here), so I'm curious about your error. What exactly does the message say, and when/where does it appear? A popup dialog when you try to launch the game?
I download the zip, extract to it's own folder, then double-click the exe file. I get a popup with the following: "The version of this file is not compatible with the version of Windows you're running. Check your computer's system information to see whether you need an x86 (32-bit) or x64 (64-bit) version of the program, and then contact the software publisher." Don't know why, and there are other unity games I can play, but I also know this is an old lappy, so if could just be something weird on my end. (Least I can play sort the court, though.)
Thanks for the details! That's my bad, I accidentally made a build for 64-bit systems only without realizing it. Try downloading the 32-bit version I've added: My Magical Friend (Windows 32bit) - hopefully that works.