Looks interesting, but I'm guessing there is a lot of stress on the recipricator mechanism that the pushrods connect to, pushing against an incline to cause the output shaft to rotate.
I agree, but in a typical combustion engine there is also a comparable amount of stress on connecting rod bearings and the typical design of a crankshaft also puts a lot of side-force on the entire piston and rod assembly.
I can't find enough information on their "reciprocator" to see how it differs from other swash/wobble-plate based axial engine designs.
It can be as beefy as it needs to be. There is no constraint there to limit the design.
It is actually an extremely flexible concept from what I can tell. Need a longer stroke? Add more angle to wobbler. Need more Torque? Expand the wobbler diameter.
There is a limit on the available angle that can be "wobbled". Once you exceed ~20 degrees IIRC, the displacements perpendicular to the stroke start causing problems.
I think the more interesting interaction is between the number of pistons and the size of the pistons.
I can't find enough information on their "reciprocator" to see how it differs from other swash/wobble-plate based axial engine designs.