1st video: most of the forces on the piston from the con rod looks to be placed on one side - not ideal. It also appears to only offer quite a short stroke.
2nd video: So that's a two stroke! I'm wondering what forces the cylinder back down on the intake stroke as all the energy looks to be lost when the top mounted valve opens?! So where is the power developed? The designer has almost all of the freshly ignited & compressed air/fuel released to any empty chamber? It also looks like the piston relies on the crank to complete the intake stroke.
James