Yeah, no pretty looking shock diamonds in that exhaust. Which makes me thing the exhaust velocity is pretty low, which I'm not too surprised by since the throat of that engine looks pretty large. And the specific impulse (efficiency) of a rocket engine is directly tied to the effective exhaust velocity [0].

Still amazingly cool, but to the other questions on this thread I'm sure the performance is not comparable to an existing rocket engine design.

[0] https://en.wikipedia.org/wiki/Specific_impulse#Specific_impu...