How is pregnancy test running doom if there’s nothing else but the plastic casing remaining of it and the ‘running doom’ part doesn’t have a single part from the original hardware? On this case it’s at least using the original display and buttons (I assume) while keeping the original hardware in place for ‘kill indicator’, but that toy itself isn’t running doom either.
I dont keep any gates, but if it’s enough that a case remains from the original hardware you can get anything bigger than your fist to run doom by ripping the guts of original out and replacing it with a raspbery pi. And in that case the only ‘hardware hacking’ is the hot glue keeping the thing together.