Architectually it's really neat layout BUT
-The old twin crank bugbear of synchronisation would be even harder here because you need very close tolerances on the piston(s) to head clerance and any inter crank harmonics are going to change those clearances dynamically.
- If I read the drawing right there are two gasket seals for each hot combustion zone - the usual block to head one and , it seems , a second one as two V-6 crankcases are bolted togehter to form the diamond shape. How you crush up first one gasket then crush up one at 90 degrees to it without everythng shifting may be bit tricky.
In a NA version as shown the big gain in piston area wil be partially offset by lower valve area to total bore area which could limit breathing.
Maybe better if it were a turbo unit with a single diamond block casting - less fire joints and CR lower so clearances less critical plus valve area maybe not a power limiter.