Should work with no issues using your original setup with the double nat - a lan port of the VZ router connected to the wan port of the netgear.
Make the netgear router a static ip address on the VZ router.
make the destination game machine a static ip address on the netgear router'
port forward the game port on the VZ router to the static ip address for the netgear router
port forward the game port on the netgear router to the static ip address for the game machine.