Agreed - that is uber-cool.
I have two questions about it, and I wonder if some of the guys with a bit more knowledge about engine internals have opinions:
#1. There are definitely fewer parts, and I get the advantages to that - but sometimes reducing number of parts will mean adding complexity to those parts. Those five pistons each look to have a U-joint required in the location that they meet the "reciprocator".
#2. With the "monoblock" constantly rotating past the fixed exhaust/intake/spark "manifold" will there be issues with maintaining a good seal?