Both files are 8086 binary, that can be used as a boot sector

I think traditionally com file are extension for dos, and img are for bios(or maybe not)

You can either use dosbox, or use the game as a boot sector program.

if you want to start the game using dosbox, just do:

"dosbox ./jumper.com"

otherwise you can use qemu:

qemu-system-x86_64 -fda jumper.img -full-screen

It's also possible to write the game as the first sector of a drive, and boot it. but I didn't test that.