How did you measure your "room temp"?
Inpingement works by having water abruptly strike an obstruction. In this design, the first inpingement is quite visible: the water comes shooting straight out against the bottom of the cup. The second inpingement is a little harder to see: after the first inpingement, the water will spread out radially, and head straight for the cup's wall. That's your second inpingement.
As you can see from the animations, the square cup doesn't let water out so easily, and that's an indication that the inpingement works, because it's pretty restrictive.
In the round cup, there is no secondary inpingement: the coolant merely flows over the cup wall. You can see how quickly the water flows out of the cup.
Flow over a baseplate (or wall) is the old design, like any of the Maze series, from DangerDen. It's ok, but not high performance. In order for that design to perform well, the coolant would have to be in turbulence, but the pumping power required to do this is higher than what all of us have used so far. It also throws another critical variable in the block design: surface smoothness versus flow restriction.
Strapping on the helmet... where's my G suit?:shrug: