if you have WB 3.1 on that 500, you could use CrossDOS, just write the game or watt ever to a 720k DOS floppy (put ducktape over the second hole on a 1.44 and format it as a 720, or just format a amiga disk as 720 on the x86 
then just mount the PC0 driver in Workbench:Storage/DOSDriver/PC0
Well, I'm going to go out on a limb here, and guess that the specs of this 500 are probably more around the 1.3 ROMS and 512k (or, if you're lucky, 1meg) RAM, no HD, one (internal) Floppy...
Now, you can still use Cross DOS on a system like that, but you're going to need an original CrossDOS disk, as well as an original Workbench disk, and a blank disk to make a bootable system with CrossDOS installed on it. Then, after creating that disk, boot the Amiga with it, mount the PC0 drive, copy the disk image (provided it fit on a 720k disk) to RAM (provided there's enough RAM). Also, transfer the ADF -> Amiga utility to RAM the 500. Then, put in another blank disk, and write the image from RAM to the disk. Then, provided that all of the disks involved were still usable, and the drive wasn't shot, you may be able to reboot and play that game. Provided the Amiga and your display device both support the game's screenmode. (You did remember to check if the game was NTSC or PAL, right?)
by the way, the amiga is complex only if you make it complex, any one could use WB with ease!!
Yeah, the above procedure sounds like it should be a snap. Especially for someone who hasn't had the large amounts of experience tinkering with the old workbench configurations, etc... Let alone the mentioned 5 year old kid.... :-D
The short of it is, yes, it's simple to point-click-drool in the Workbench. This isn't one of those tasks, though...
