I sometimes see the term Boxer used to describe the ACVW engine. In my experience, it ain't so because a 'boxer' has the directly opposed piston traveling to and away from the crank center at the same time - in other words like a boxer hitting his own gloves.
The original aircooled BMW motorcycle was a real 'boxer'. And at one point, the Japanese MC makers were modifying 4-cylinder V-engines into 'Big Bang' engines to make two cylinders fire at once. More low-RPM torque.
Hummm.. might be interesting to make a Big Bang Boxer of an ACVW.
Okay, I really don't have that much time on my hands to dream up this stuff. :)